Immune-mediated necrotising myopathy is a rare statin-associated adverse effect: a case report

Hong Kong Academy of Medicine. CC BY-NC-ND 4.0
 
CASE REPORT
Immune-mediated necrotising myopathy is a rare statin-associated adverse effect: a case report
KF Lee, FRCP, FHKAM (Medicine); Maria WH Mak, MRCP, FHKAM (Medicine); Virginia WN Lao, MRCP, FHKAM (Medicine); Helen LK Yip, MRCP, FHKAM (Medicine); WY Lau, MRCP, FHKAM (Medicine); Victor TL Wong, MRCP, FHKAM (Medicine)
Department of Medicine and Geriatrics, Kwong Wah Hospital, Hong Kong
 
Corresponding author: Dr KF Lee (leekf1@ha.org.hk)
 
 Full paper in PDF
 
Case report
The patient was a 60-year-old woman with a 14-year history of type 2 diabetes mellitus and dyslipidaemia with a complication of background diabetic retinopathy. In December 2016, during a routine follow-up examination, the patient was found to have asymptomatic 5-fold rise in liver aminotransferases. The patient’s glycosylated haemoglobin level was 8.5% and her low-density lipoprotein cholesterol (LDL-C) level was 2.0 nmol/L. She was taking metformin 500 mg 3 times daily, gliclazide 160 mg and vildagliptin 50 mg twice daily, and atorvastatin 20 mg once daily. In view of the possibility of statin-related hepatotoxicity, atorvastatin was withheld after 22 months of treatment. However, transaminitis persisted over the following 6 months after exclusion of viral hepatitis and any structural abnormality. After 2 months, the patient complained of bilateral thigh weakness (Medical Research Council grade 4/5) and myalgia that prevented her from climbing stairs. Blood tests revealed elevated levels of creatinine kinase (CK) [5426 IU/L; normal range, 26-192 IU/L], alanine aminotransferase (294 IU/L; normal range, <47 IU/L), aspartate aminotransferase (164 IU/L; normal range, <36 IU/L), and lactate dehydrogenase (722 IU/L; normal range, 110-210 IU/L). Other inflammatory markers for myositis including anti-Jo-1 antibodies were normal. Urine for myoglobulin was negative and renal function was normal. With persistent clinical and biochemical abnormalities 9 months after statin cessation and no history of potential drug or health products that might induce myositis, immune-mediated necrotising myopathy (IMNM) associated with statins was suspected. Electromyography suggested active myopathic changes while muscle biopsy revealed atrophy of multiple muscle fibres, necrosis and regeneration without inflammatory infiltrates. Diagnosis was finally confirmed following an enzyme-linked immunosorbent assay by a marked elevation of anti–3-hydroxy-3-methylglutaryl-CoA reductase (anti-HMGCR) autoantibody to >200 IU/mL (normal range, <20 IU/mL). Considering her reasonable glycaemic control, monotherapy with intravenous immune globulin (IVIG) was initiated at a rate of 2 g per kilogram body weight per month. Muscle power increased and CK decreased (Fig) so IVIG was stopped after 6 months. Nonetheless her muscle weakness worsened and extended to involve the upper limbs as well as her ability to swallow, and CK rose from 3200 IU/L to almost 8000 IU/L after 2 months. High-dose glucocorticoids (intravenous methylprednisolone 500 mg/day for 3 days followed by oral prednisolone 45 mg/day) and cyclosporin were started. A monthly IVIG infusion was also added in the initial 2 months to enhance the therapeutic effect for her severe myopathy. After 4 months, her weakness improved and CK dropped below 1000 IU/L. Owing to deteriorating glycaemic control (glycosylated haemoglobin level deteriorated to 9.1%) and acute glaucoma, early tapering of glucocorticoid dose was considered. However, serum CK level returned to 2000 IU/L when prednisolone dose was weaned down to 7.5 mg daily, although she retained full muscle power. Another steroid-sparing agent, either methotrexate or rituximab, was considered.
 

Figure. Clinical course and response to different modalities of treatment in a patient with immune mediated necrotising myopathy associated with statin use
 
Discussion
Statins are well-proven lipid-lowering drugs that reduce LDL-C and hence cardiovascular morbidity and mortality, in both primary and secondary prevention. Their use is recommended in a wide range of patients and high intensity therapy (LDL-C reduction ≥50%) is indicated in a significant proportion.1
 
Despite their acceptable side-effect profile, about 10% of patients report statin-associated muscle symptoms (SAMS) such as myalgia and/or weakness.2 Toxic myopathy, defined as SAMS with marked elevation (>10 times the upper limit of normal) of CK, occurs in approximately 1 in 10 000 patients treated with statins per year. Typically, this condition remits spontaneously with cessation of statin use. On the contrary, statin-associated IMNM, a rarer adverse effect with an estimated occurrence of 2 to 3 per 100 000 treated patients, is unlikely to be resolved by statin withdrawal, despite having similar SAMS and muscle enzyme increment.3 The IMNM was only suspected in our case 9 months after cessation of statin therapy, probably due to an initial lack of SAMS and misinterpretation that the elevated aminotransferases originated from the liver rather than muscle. It is important to also check CK in asymptomatic statin users with elevated aminotransferase levels to enable early diagnosis of statin-associated myopathy.
 
The IMNM is now recognised as a distinct form of myositis, usually presenting with symmetrical proximal arm or leg weakness with marked elevation of CK (>10 times the upper limit of normal), muscle oedema, and atrophy on magnetic resonance imaging. In addition, muscle cell necrosis and regeneration along with minimal inflammatory infiltrates in muscle biopsy is evident and irritable myopathy on electromyography.3 Our patient had clinical features compatible with most of these symptoms. Unlike other SAMS phenotypes, there are no identifiable risk factors such as lipophilic (vs hydrophilic) statins, high-dose statins, old age, female gender, small body frame, liver or renal failure, and concomitant medications metabolised by the same hepatic P450 isoforms2 in statin-associated IMNM (Table). The detection of anti-HMGCR autoantibody in 2010 revolutionised the pathophysiology, diagnosis, disease classification, and treatment of this disease entity. This autoantibody detected by means of an enzyme-linked immunosorbent assay is both sensitive and specific; it has been detected in 24 of 26 patients (92%) with a clinical presentation compatible with statin-associated IMNM although it has not been detected in statin-treated patients who do not have SAMS or self-limiting toxic myopathy. The overall specificity of the commercial enzyme-linked immunosorbent assays for anti-HMGCR autoantibody may be as high as 99.3%.4 Nevertheless anti-HMGCR autoantibodies can also be detected in patients with IMNM who have an underlying malignancy or who are statin-naïve, particularly with more widespread use of anti-HMGCR autoantibody in patients with myopathy. With the detection of another autoantibody against a signal recognition particle, in 2017 the European Neuromuscular Centre classified IMNM into three subtypes: anti–signal recognition particle myopathy, anti-HMGCR myopathy and antibody-negative IMNM.3 Although these subtypes share similar clinical features to those mentioned above, they differ in environmental risk factors, genetic risk factors, cancer risks, extra-muscular manifestations, and response to different treatment modalities and prognoses.
 
Although spontaneous improvement after statin cessation has been reported in case studies, most patients with this condition require one to two immunosuppressive agents, usually in the form of high-dose glucocorticoids plus one of the following; methotrexate, azathioprine, mycophenolate mofetil or cyclosporine, for initial disease control.4 5 The IVIG has also been used successfully as first-line monotherapy and it may be considered in those with pre-existing diabetes, as in our patient.6 However, incomplete normalisation of CK and the need for a prolonged course of treatment suggests its inability to completely abolish the pathophysiological process that causes muscle damage. This was illustrated in our patient with a rebound in CK level 2 months after completion of a 6-month course of IVIG monotherapy. Rather, her condition stabilised following treatment with two immunosuppressants, prednisolone and cyclosporine, although her anti-glycaemic treatment needed to be intensified. Similar to the clinical course of other reported series, her condition relapsed upon weaning of glucocorticoid dosage.7 Apart from escalation of steroid dosage, other steroid sparing agents may need to be considered. Rituximab has emerged as a promising rescue agent in this situation.8 Lastly, as statin is a known trigger of anti-HMGCR autoantibody, re-challenge with any statin should be avoided and an alternative cholesterol-lowering agent such as ezetimibe or PCSK9 inhibitors can be considered.9
 
In conclusion, IMNM can occur rarely in patients who present with SAMS. Unlike toxic myopathy, clinical and biochemical abnormalities persist upon statin withdrawal and immunosuppressants are usually required for disease control.
 
Author contributions
All authors contributed to the concept or design of the study, acquisition of the data, analysis or interpretation of the data, drafting of the manuscript, and critical revision of the manuscript for important intellectual content. All authors had full access to the data, contributed to the study, approved the final version for publication, and take responsibility for its accuracy and integrity.
 
Conflicts of interest
All authors have disclosed no conflicts of interest.
 
Funding/support
This case report received no specific grant from any funding agency in the public, commercial or not-for-profit sectors
 
Ethics approval
The patient was treated in accordance with the Declaration of Helsinki. The patient provided written informed consent for all treatments and procedures.
 
References
1. Grundy SM, Stone NJ, Bailey AL, et al. 2018 AHA/ ACC/AACVPR/AAPA/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA Guideline on the Management of Blood Cholesterol: A report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Circulation 2019;139:e1082-143. Crossref
2. Ward NC, Watts GF, Eckel RH. Statin toxicity. Circ Res 2019;124:328-50. Crossref
3. Pinal-Fernandez I, Casal-Dominguez M, Mammen AL. Immune-mediated necrotizing myopathy. Curr Rheumatol Rep 2018;20:21. Crossref
4. Mammen AL. Statin-associated autoimmune myopathy. N Engl J Med 2016;374:664-9. Crossref
5. Tiniakou E, Christopher-Stine L. Immune-mediated necrotizing myopathy associated with statins: history and recent developments. Curr Opin Rheumatol 2017;29:604- 11. Crossref
6. Mammen AL, Tiniakou E. Intravenous immune globulin for statin-triggered autoimmune myopathy. N Engl J Med 2015;373:1680-2. Crossref
7. Ramanathan S, Langguth D, Hardy TA, et al. Clinical course and treatment of anti-HMGCR antibody– associated necrotizing autoimmune myopathy. Neurol Neuroimmunol Neuroinflamm 2015;2:e96. Crossref
8. Allenbach Y, Mammen AL, Benveniste O, Stenzel W; Immune-Mediated Necrotizing Myopathies Working Group. 224th ENMC International Workshop: Clinicosero- pathological classification of immune-mediated necrotizing myopathies Zandvoort, The Netherlands, 14-16 October 2016. Neuromuscul Disord 2018;28:87-99. Crossref
9. Albayda J, Christopher-Stine L. Identifying statinassociated autoimmune necrotizing myopathy. Cleve Clin J Med 2014;81:736-41. Crossref

Parapharyngeal space lipoma: a case report

Hong Kong Academy of Medicine. CC BY-NC-ND 4.0
 
CASE REPORT
Parapharyngeal space lipoma: a case report
Herbert SH Lee, MB, ChB (CUHK); CM Ngai, MB, BS, FHKAM (Otorhinolaryngology)
Department of Otorhinolaryngology, Head and Neck Surgery, Yan Chai Hospital, Kowloon West Cluster, Hong Kong
 
Corresponding author: Dr Herbert SH Lee (herbertshlee@link.cuhk.edu.hk)
 
 Full paper in PDF
 
Introduction
Parapharyngeal space (PPS) tumours account for only around 0.5% of tumours in the head and neck region.1 Most are benign in nature and salivary in origin.2 Lipomas in the PPS are rare, despite being the most common benign mesenchymal head and neck tumour.3 4 Other lesions that may be encountered in this area include neurogenic tumours, chemodectomas, branchial cysts, and metastatic lesions.
 
Case report
A middle-aged woman first presented to the outpatient clinic in April 2019 with a 3-year history of left painless neck mass, with gradual growth but no other symptoms. Physical examination revealed a soft neck mass of around 4 to 5 cm in diameter over the left level III region. Other ear, nose and throat examinations, including flexible laryngoscopy, were unremarkable.
 
Initial fine-needle aspiration cytology (FNAC) was inadequate for diagnosis. A second FNAC revealed sparse adipose tissue. Ultrasound showed a 2.68×1.52×2.41 cm deeply located hypoechoic lesion on the left submandibular region, with internal striations resembling those of subcutaneous fat. No vascularity was detected on colour Doppler scan. Oval lymph nodes with preserved fatty hilum were seen at bilateral upper cervical regions. They all had a sub-centimetre short axis, likely reactive in nature. The overall sonographic impression was of lipoma. Magnetic resonance imaging (MRI) revealed a 3.6×4.9×9.2 cm (anteroposterior × transverse × craniocaudal planes) well-circumscribed, lobulated mass in the left PPS. The lesion was of fat signal intensity, with faint fluffy internal enhancing septation but no internal enhancing solid nodule seen, nor frank invasion into the surrounding structures (Fig 1a). The lesion extended from the level of C1 to C7 (Fig 1b), bulging medially onto the left side of the oropharynx and displacing the left carotid space content posterolaterally (Fig 1c). The MRI findings were suggestive of a lipomatous lesion. The overall clinical picture was compatible with a parapharyngeal lipoma. Although parapharyngeal lipoma is a benign lesion, gradual growth and consequent mass effects can occur. As the patient was only middle-aged, complications such as dysphagia, shortness of breath, and obstructive sleep apnoea were possible if the tumour was allowed to continue growing. After explaining to the patient the clinical, FNAC and imaging findings, as well as potential complications arising from the tumour, she was keen to undergo surgical excision.
 

Figure 1. (a) Coronal magnetic resonance image showing a mass lesion of fat signal intensity in the left parapharyngeal space. (b) Sagittal magnetic resonance image showing the extent of the lesion from C1 to C7. (c) Axial magnetic resonance image showing displacement of the oropharynx and left carotid space by the lesion
 
During out-patient preoperative assessment in July 2019, the patient complained of recent dull vague pain in the throat. Physical examination revealed the hyoid bone to be deviated to the right. Subsequent flexible laryngoscopy demonstrated a swelling on the left lateral oropharyngeal wall.
 
Surgery under general anaesthesia was performed in August 2019 and the sternocleidomastoid muscle was dissected from the lipoma. The lipoma was subsequently dissected from the internal jugular vein and the carotid artery and completely excised (Fig 2). Haemostasis was achieved and a drain inserted prior to skin closure. The entire operation took about 2 hours with intra-operative blood loss of around 50 mL. The patient was discharged 5 days later with no complications noted.
 

Figure 2. (a) Intra-operative photograph showing the lipoma. (b) Photograph of the excised parapharyngeal lipoma
 
At postoperative follow-up 9 days later the patient was clinically well with no active complaints. She was tolerating an oral diet and the wound had healed well. Flexible laryngoscopy showed no more oropharyngeal wall swelling. Pathology results confirmed that the left parapharyngeal lesion was a lipoma and the excised left level III lymph node had no evidence of malignancy.
 
Discussion
The PPS is anatomically described as an inverted pyramid with the apex and the base at the greater cornu of the hyoid and the skull base, respectively. The posterior boundary is the vertebral column and paravertebral muscles. Anteriorly, it is limited by the junction of pterygoid fascia to the buccinator muscle fascia, the pterygomandibular raphe, and the submandibular gland. The medial boundary is formed by the superior constrictor muscle and the tonsillar fossa. The lateral boundary is formed by the medial pterygoid muscle, the ramus of mandible, parotid gland, and the posterior belly of the digastric muscle. The PPS can be subdivided into pre-styloid and post-styloid compartments by the styloid process. The post-styloid compartment consists of several vital structures including the 9th to 11th cranial nerves, internal carotid artery, internal jugular vein, and cervical sympathetic trunk. The pre-styloid compartment may contain the deep lobe of the parotid gland or accessory salivary tissues, as well as lymph nodes. A lipoma found in the pre-styloid compartment of the PPS is indeed very rare.
 
A lipoma is an encapsulated, benign, subcutaneous, and submucosal tumour composed of mature adipose tissue cells. Most PPS lipomas grow insidiously and cause symptoms only when exerting mass effects as seen in any other benign tumours, for example, dysphagia, shortness of breath, and obstructive sleep apnoea. Occasionally, due to obstruction of the Eustachian tube by the tumour, otitis media with effusion and conductive hearing loss may occur. Hoarseness and tongue muscle weakness resulting from compression of the lower cranial nerves, as well as Horner’s syndrome and trismus owing to involvement of the cervical sympathetic trunk and medial pterygoid respectively are all suggestive of malignancy.
 
Diagnostic FNAC is often technically difficult as the PPS lipoma is deep-seated. Most of the time, imaging such as computed tomography (CT) and MRI has significant diagnostic significance. On computed tomography scan, a lipoma is revealed as a homogenous and hypodense mass with no enhancement. In contrast, MRI scan is the most ideal imaging modality due to its excellent delineation of soft tissue and multiplanar capability. Lipomas appear as hyperintense on T1- and T2-weighted sequences with internal septations. T1-weighted sequences with fat suppression demonstrate even more obvious contrast with the surrounding soft tissues.
 
Surgical excision is the treatment of choice. The surgical approach depends on tumour size, location, and relationship to major vessels. A transcervical approach is most widely applied and is particularly suitable for smaller PPS tumours. Some literature suggests a transcervical approach for tumours as large as 8 cm,5 6 but there is no consensus on the cut-off size. Our case demonstrates that the transcervical approach can achieve good exposure for a parapharyngeal tumour extending from level C1 to C7, 9.2 cm at its greatest dimension. Advantages of a transcervical approach include adequate exposure of vital structures and a lower risk of damage to the facial nerves. A transcervical approach is combined with a transmandibular approach when dealing with larger lesions involving the skull base and the aforementioned lower cranial nerves for better exposure, while an infratemporal approach is used when access to the lateral part of the skull base is necessary. A transoral approach, which was used in the past, is now out of favour as the exposure offered by this route is very poor. There is also a higher risk of vascular and neural injury that makes this approach unsafe.
 
Conclusion
Parapharyngeal space lipomas are rarely seen in our daily practice but deserve more of our attention since they are easily missed in the early stages and seen as a non-specific neck mass as in this case. Magnetic resonance imaging scan is useful not only in terms of diagnostic superiority, but also for preoperative planning. A transcervical approach is most commonly adopted for PPS tumours as it is associated with lower surgical risk by providing excellent exposure of vital neurovascular structures.
 
Author contributions
Concept or design: CM Ngai.
Acquisition of data: HSH Lee.
Analysis or interpretation of data: HSH Lee.
Drafting of the manuscript: HSH Lee.
Critical revision of the manuscript for important intellectual content: CM Ngai.
 
All authors had full access to the data, contributed to the study, approved the final version for publication, and take responsibility for its accuracy and integrity.
 
Conflicts of interest
All authors have disclosed no conflicts of interest.
 
Funding/support
This case report received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
 
Ethics approval
The study was conducted in accordance with guidelines by the Kowloon West Cluster ethics committee. Informed consent was obtained from the patient.
 
References
1. Carrau RL, Johnson JT, Myers EN. Management of tumors of the parapharyngeal space. Oncology (Williston Park) 1997;11:633-40.
2. Batsakis JG, Sneige N. Parapharyngeal and retropharyngeal space diseases. Ann Otol Rhinol Laryngol 1989;98:320-1. Crossref
3. Abdullah BJ, Liam CK, Kaur H, Mathew KM. Parapharyngeal space lipoma causing sleep apnoea. Br J Radiol 1997;70:1063-5. Crossref
4. Ulku CH, Uyar Y. Parapharyngeal lipoma extending to skull base: a case report and review of the literature. Skull Base 2004;14:121-5. Crossref
5. Smith JC, Snyderman CH, Kassam AB. Giant parapharyngeal space lipoma: case report and surgical approach. Skull Base 2002;12:215-20. Crossref
6. Carrau RL, Myers EN, Johnson JT. Management of tumors arising in the parapharyngeal space. Laryngoscope 1990;100:583-9. Crossref

Indocyanine green fluorescence-guided pulmonary wedge resection in a child: a case report

© Hong Kong Academy of Medicine. CC BY-NC-ND 4.0
 
CASE REPORT
Indocyanine green fluorescence-guided pulmonary wedge resection in a child: a case report
CH Fung, MB, BS, MRCS; CT Lau, MB, BS, FRCS; Kenneth KY Wong, PhD, FRCS
Department of Surgery, The University of Hong Kong, Hong Kong
 
Corresponding author: Dr CH Fung (fungchiheng@gmail.com)
 
 Full paper in PDF
 
Case report
Tissue diagnosis of pulmonary nodules of an undetermined nature can be achieved with thoracoscopic wedge resection. However, localisation of a lesion during surgery can be technically demanding, especially for small deep-seated lesions. We report our technique of indocyanine green (ICG) fluorescence-guided pulmonary wedge resection in a child.
 
A 4-year-old boy presented with pyrexia of unknown origin associated with cough for 2 weeks. Extensive septic workup including sputum culture, chest X-ray, nasopharyngeal aspirate and urine culture were unremarkable. Mantoux test was positive. Computed tomographic (CT) scan of the thorax to look for occult chest infection showed features suggestive of pulmonary tuberculosis and a 6-mm nodule over the apical segment of the left lower lobe. He completed a 6-month course of antitubercular medication but reassessment scan after 9 months showed a persistent left lower lobe pulmonary nodule and he was referred to our surgical unit for tissue diagnosis.
 
The patient underwent CT-guided localisation of the pulmonary nodule under general anaesthesia 1 hour prior to thoracoscopic wedge resection. The pulmonary nodule was identified at the apical segment of the left lower lobe, 1.3 cm from the pleural surface (Fig 1). An 18-gauge guiding needle was inserted by the radiologist to the lesion under CT guidance. Methylene blue (0.5 mL) and ICG (0.5 mL) were injected around the lesion via the guiding needle. A hookwire was also placed for localisation as safety backup and adjunct to ICG. The patient was then transferred back to the operating theatre. The target lesion was identified thoracoscopically with guidance of methylene blue dye and ICG fluorescence (KARL STORZ OPAL1®). Wedge resection of the target lesion was performed with Endo GIA™ Ultra Universal 30-mm staplers (Medtronic). Complete excision was confirmed by absence of fluorescence in the remaining left lower lobe on ICG fluorescence imaging (Fig 2). The use of ICG fluorescence enhanced intra-operative localisation of the small pulmonary nodule and facilitated a minimally invasive operation. The patient made an uneventful recovery and was discharged 2 days after surgery. Histology of the wedge-resected specimen confirmed complete excision and showed granulomatous inflammation with focal necrosis and no evidence of malignancy. The patient had resumed full activity at follow-up 1 week after surgery.
 

Figure 1. Preoperative coronal computed tomography of thorax showing the undetermined lesion (arrow)
 

Figure 2. Intra-operative photo showing the segment of lung stained by methylene blue under normal light (a); the same segment of lung seen with indocyanine green fluorescence (b); the wedge of excised lung under normal light (c), and with indocyanine green fluorescence (d), confirming complete resection
 
Discussion
Intra-operative localisation of small pulmonary nodules remains a challenge for prompt and complete resection of lesions. It is recommended that preoperative localisation should be performed prior to minimally invasive resection for pulmonary nodules <10 mm in diameter or >5 mm from the pleural surface.1 Various means of preoperative localisation have been reported in children including micro-coil insertion, methylene blue dye injection, and radiotracer labelling.2 Hookwire is reported to be safe and useful for localisation of lung nodules in children as well as other situations such as thoracoscopic resection of deep-seated congenital cystic adenomatoid malformation.2 3 Although these methods are considered feasible in children, they have their own limitations and risks, such as local trauma and issues of inaccuracy in small lesions for hookwire localisation; difficulty in revealing deep lesions and diffuse spillage in small lesions of methylene blue dye. Efforts have been made to find a convenient, safe, and clear method for localisation.
 
The United States Food and Drug Administration has recently extended the approved uses of ICG to include sentinel lymph node biopsy in various types of tumour, assessment of blood supply in anastomosis and reconstructive flaps and enhanced visualisation of biliary anatomy during laparoscopic cholecystectomy.4 In thoracic surgery, it is a useful aid to sentinel lymph node mapping, lung mapping, oesophageal conduit vascular perfusion, and lung nodule identification.5 To date, no data about the use of ICG in thoracoscopic wedge resection in paediatric patients have been reported. In our experience, ICG preoperative localisation is a safe and feasible means to help achieve prompt and complete thoracoscopic wedge resection of small pulmonary nodules. It appeared to be more accurate than hookwire localisation in this patient, allowing immediate clear visualisation when guiding the extent of resection. It also facilitated easy assessment of completeness of resection.
 
In conclusion, ICG fluorescence is a safe and feasible method of localisation prior to thoracoscopic wedge resection of a pulmonary nodule in children.
 
Author contributions
All authors contributed to the concept or design of the study, acquisition of the data, analysis or interpretation of the data, drafting of the manuscript, and critical revision of the manuscript for important intellectual content. All authors had full access to the data, contributed to the study, approved the final version for publication, and take responsibility for its accuracy and integrity.
 
Conflicts of interest
As an editor of the journal, KKY Wong was not involved in the peer review process. Other authors have disclosed no conflicts of interest.
 
Funding/support
This case report received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
 
Ethics approval
The patient was treated in accordance with the Declaration of Helsinki. The patient provided written informed consent for all procedures.
 
References
1. Suzuki K, Nagai K, Yoshida J, et al. Video-assisted thoracoscopic surgery for small indeterminate pulmonary nodules: indications for preoperative marking. Chest 1999;115:563-8. Crossref
2. Polites SF, Fahy AS, Sunnock WA, et al. Use of radiotracer labeling of pulmonary nodules to facilitate excisional biopsy and metastasectomy in children with solid tumors. J Pediatr Surg 2018;53:1369-73. Crossref
3. Lau CT, Wong KK. Thoracoscopic resection of congenital cystic adenomatoid malformation in a patient with fused lung fissure using hookwire. Innovations (Phila) 2018;13:226-9. Crossref
4. Namikawa T, Sato T, Hanazaki K. Recent advances in near-infrared fluorescence-guided imaging surgery using indocyanine green. Surg Today 2015;45:1467-74. Crossref
5. Okusanya OT, Hess NR, Luketich JD, Sarkaria IS. Infrared intraoperative fluorescence imaging using indocyanine green in thoracic surgery. Eur J Cardiothorac Surg 2018;53:512-8. Crossref

Indocyanine green fluorescence-assisted laparoscopic hepatectomy for hepatocellular carcinoma in a pre-adolescent girl: a case report

© Hong Kong Academy of Medicine. CC BY-NC-ND 4.0
 
CASE REPORT
Indocyanine green fluorescence-assisted laparoscopic hepatectomy for hepatocellular carcinoma in a pre-adolescent girl: a case report
Patrick HY Chung, MB, BS, FHKAM (Surgery); Kenneth SH Chok, MB, BS, FHKAM (Surgery); Kenneth KY Wong , MB, ChB, FHKAM (Surgery)
Department of Surgery, The University of Hong Kong, Hong Kong
 
Corresponding author: Dr Kenneth KY Wong (kkywong@hku.hk)
 
 Full paper in PDF
 
Case report
We present the case of a 9-year-old Chinese girl who presented with an incidental finding of elevated alkaline phosphatase (349 U/L) during a routine medical examination in 2018. Further blood test results were positive for hepatitis B. The patient was prescribed entecavir 0.5 mg daily and underwent regular liver ultrasound scans. After 6 months, a tumour at the right lobe of the liver was identified during routine scanning, and serum alpha-fetoprotein was elevated at 489 ng/mL. Further investigation with contrast computed tomography scan revealed a 3.8-cm × 5.0-cm tumour at segment 5 of the liver with radiological features compatible with hepatocellular carcinoma (HCC, Fig 1a). Liver function tests were normal (total bilirubin: 12 μmol/L, albumin 38 g/L, international normalised ratio:1.1). The patient’s body weight was 28 kg and her height was 128 cm.
 

Figure 1. A 9-year-old Chinese girl with a tumour at segment 5 of the liver. (a) Computed tomography scan showing a 3.8-cm × 5.0-cm arterial enhancing hepatocellular carcinoma at segment 5 of the liver. (b) A 5-cm solitary tumour was identified on the surface of segment 5 under laparoscopy.The tumour became more distinguishable under near infrared fluorescence
 
Laparoscopic segment 5 resection was suggested. Intravenous indocyanine green (ICG) at a dosage of 0.5 mg/kg was administered 24 hours before surgery with no adverse effects. The following day, laparoscopic hepatectomy (LH) was performed under general anaesthesia. The patient was placed in a reverse Trendelenburg position with her right side mildly elevated and three 10-mm and two 5-mm abdominal ports created. Intra-operatively, a 5-cm solitary tumour was identified on the surface of segment 5 and it became more distinguishable under fluorescence (Fig 1b). Near-infrared fluorescence imaging and intra-operative ultrasound scan revealed no further tumours. The liver was not cirrhotic, and the surface was smooth. Guided by the fluorescent signal, a 1-cm resection margin was marked and hepatic transection performed using laparoscopic ultrasonic dissectors. The segmental branches of the hepatic vessels and bile ducts were controlled with non-absorbable polymer clips prior to division. The resected specimen was retrieved via a 5-cm Pfannenstiel incision. The operation was uneventful and lasted for 3 hours. Total blood loss was 30 mL and no blood products were required.
 
Postoperatively the patient was extubated and she was able to eat and drink on the same day. Wound pain was well controlled by oral paracetamol (15 mg/kg/dose) and she was transferred from the intensive care unit to a general ward the following day. She was able to walk on day 2 after surgery and made an uneventful recovery. She was discharged home on day 6 after surgery with normal liver function. Histological analysis of the resected liver confirmed the presence of a 5-cm moderately differentiated HCC with clear resection margins. The patient returned to school 14 days after surgery. Out-patient review at 3 months revealed healing of her surgical wounds with minimal scarring. The Pfannenstiel scar was not seen. Histological analysis of the resected specimen showed clear liver parenchymal and bile duct resection margins (Fig 2).
 

Figure 2. Histological analysis of the resected specimen confirmed clear liver parenchymal and bile duct resection margins (haematoxylin and eosin, 40×)
 
Discussion
Since the early 2000s, there have been significant advances in paediatric minimally invasive surgery owing to the availability of smaller-sized instruments as well as increasing technical expertise. However, the development of paediatric LH has advanced more slowly, even though it was first performed over 10 years ago in adults with proven benefit, especially in minor liver resection.1 Given the advantages of LH, including a smaller incision, less blood loss, early return of bowel function and rapid recovery, we believe this surgical approach should be extended to children with liver tumour. Our patient recovered quickly from her LH with only paracetamol required for pain control, largely due to the less invasive nature of the surgery. She was also able to resume her usual activities much earlier than usual for patients who underwent open hepatectomy. Although a Pfannenstiel incision was required, the small scars over the visible part of her abdomen would be more cosmetically acceptable to a young adolescent. Intra-operatively, conventional laparoscopic instruments are usually sufficient with no need for specialised equipment. The absence of liver cirrhosis and consequent minimal blood loss also favoured LH in our patient.
 
Of particular interest in this case was the use of ICG fluorescence for intra-operative tumour navigation. The ICG is a hydrosoluble molecule that has been used for the evaluation of hepatic function prior to liver resection. The clinical application of its fluorescent properties during HCC resection was first reported in 2009.2 Following intravenous injection, ICG is protein-bound and becomes fluorescent under infrared light. In the liver, ICG is taken up by normal hepatocytes and excreted in bile after 4 to 6 hours. However, in tumour cells, the excretion is inhibited and ICG will accumulate. Tumour tissue will thus remain fluorescent and this facilitates real-time identification of a primary tumour as well as any metastatic lesions under infrared light.3 The benefit of ICG fluorescence is more important during laparoscopic surgery since its fluorescent property compensates for the inability of LH to examine the whole liver in its absence. The tumour margin is also more obvious under ICG fluorescence imaging as the tumour appears much brighter. In addition, ICG fluorescence helps to differentiate a non-cancerous lesion detected by intra-operative ultrasound. Regarding the timing of injection, previous studies have suggested that it should be administered at least 48 hours before surgery to decrease the background fluorescence.4 In our case, the injection time was 24 hours before surgery but the fluorescent signal was still intense with good tumour-to-liver contrast. The exact timing for ICG injection remains undetermined. Normal hepatic function that promotes ICG excretion and that was present in our patient may have enabled the shorter time interval between injection and operation which in turn translated into a shorter hospitalisation.
 
In conclusion, LH is feasible in paediatric patients and should be considered as a surgical approach for children with liver cancer, especially when minor hepatectomy is required. It is associated with a speedier recovery after surgery with minimal scarring, both of which are important for the physical as well as psychosocial well-being of a growing child. Furthermore, ICG fluorescence is safe for use in children and provides an additional method to assist intra-operative tumour identification. The best timing of injection requires further study.
 
Author contributions
Concept or design: PHY Chung.
Acquisition of data: PHY Chung, KSH Chok.
Analysis or interpretation of data: PHY Chung.
Drafting of the manuscript: PHY Chung, KKY Wong.
Critical revision of the manuscript for important intellectual content: KSH Chok, KKY Wong.
 
Conflicts of interest
As an editor of the journal, KKY Wong was not involved in the peer review process. Other authors have disclosed no conflicts of interest.
 
Acknowledgement
The authors would like to acknowledge Prof John Nicholls from the Department of Pathology, The University of Hong Kong for his valuable contribution in preparing Figure 2.
 
Funding/support
This case report received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
 
Ethics approval
This study was approved by the hospital ethics committee and was carried out in accordance with the principles outlined in the Declaration of Helsinki. Consent from the patient and her mother were obtained. This report does not contain any information by which they could be identified.
 
References
1. Mirnezami R, Mirnezami AH, Chandrakumaran K, et al. Short- and long-term outcomes after laparoscopic and open hepatic resection: systematic review and meta-analysis. HPB (Oxford) 2011;13:295-308. Crossref
2. Gotoh K, Yamada T, Ishikawa O, et al. A novel image- guided surgery of hepatocellular carcinoma by indocyanine green fluorescence imaging navigation. J Surg Oncol 2009;100:75-9. Crossref
3. Souzaki R, Kawakubo N, Matsuura T, et al. Navigation surgery using indocyanine green fluorescent imaging for hepatoblastoma patients. Pediatr Surg Int 2019;35:551-7. Crossref
4. Ishizawa T, Fukushima N, Shibahara J, et al. Real-time identification of liver cancers by using indocyanine green fluorescent imaging. Cancer 2009;115:2491-504. Crossref

Gynaecological transurethral resection of the prostate syndrome–induced acute pulmonary oedema treated with high-dose nitro-glycerine: a case report

© Hong Kong Academy of Medicine. CC BY-NC-ND 4.0
 
CASE REPORT
Gynaecological transurethral resection of the prostate syndrome–induced acute pulmonary oedema treated with high-dose nitro-glycerine: a case report
SH Huang, MD1; SW Chang, MD2; AY Wang, MD3,4,5
1 Department of Surgery, Taipei Medical University Hospital, Taipei City, Taiwan
2 Division of Acute Care Surgery and Traumatology, Department of Surgery, Taipei Medical University Hospital, Taipei City, Taiwan
3 Department of Emergency Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei City, Taiwan
4 Graduate Institute of Injury Prevention and Control, College of Public Health, Taipei Medical University, Taipei City, Taiwan
5 Department of Critical Care Medicine, Taipei Medical University Hospital, Taipei City, Taiwan
 
Corresponding author: Dr AY Wang (anyimilk@gmail.com)
 
 Full paper in PDF
 
Case report
A previously healthy 48-year-old woman developed acute respiratory distress during operative hysteroscopy for submucosal myomectomy. The preoperative chest X-ray was normal (Fig a). During surgery, facial oedema and acute dyspnoea developed following intrauterine irrigation with 19 100 mL normal saline. Analysis of arterial blood showed mixed metabolic acidosis and respiratory acidosis with pH 6.989, PaCO2 57.8 mm Hg, and a bicarbonate concentration of 14.0 mmol/L (Table). Desaturation developed progressively and her SpO2 was 85% with O2 mask at a flow rate of 10 L/min. The PaO2/FiO2 ratio was 121.5 mm Hg.
 

Figure. A 48-year-old woman who developed acute respiratory distress during operative hysteroscopy for submucosal myomectomy. (a) Normal preoperative chest radiograph; (b) cardiac ultrasound showing preserved left ventricular systolic function and trivial mitral regurgitation with no regional wall motion abnormality; (c) chest radiograph after hysteroscopy showing bilateral perihilar haziness, consistent with pulmonary oedema; (d) chest radiograph showing resolution of bilateral pulmonary oedema the day after surgery
 

Table. Time course of arterial blood gases for a 48-year-old woman who developed acute respiratory distress during operative hysteroscopy for submucosal myomectomy. At 1 hour after diuretic use, the arterial blood gas showed deterioration of the PaO2/FiO2 ratio. Following a high-dose nitro-glycerine bolus and continuous nitro-glycerine infusion with diuretic and bi-level positive airway pressure support, PaO2/FiO2 ratio increased
 
On arrival in the intensive care unit, the patient had a blood pressure of 160/90 mm Hg, heart rate 72 bpm, respiratory rate 30 breaths per minute, and SpO2 84%. Chest auscultation revealed bilateral crackles and point-of-care ultrasonography showed a bilateral diffuse B-line pattern consistent with acute pulmonary oedema. Cardiac ultrasound revealed preserved left ventricular systolic function (75.01%) [Fig b]. There was neither regional wall motion abnormality nor aortic stenosis. Non-invasive positive pressure ventilation with bi-level positive airway pressure was commenced to assist ventilation. Subsequent chest X-ray showed acute pulmonary oedema (Fig c) and intravenous diuretic (furosemide, 40 mg) was administered; nevertheless her PaO2/FiO2 ratio dropped to 80.5 mm Hg (Table). The overall presentation was compatible with gynaecological transurethral resection of the prostate (TURP) syndrome–induced acute pulmonary oedema.
 
Intravenous high-dose 1 mg nitro-glycerine (NTG) was administered followed by 1 mg NTG bolus 5 minutes later and continuous infusion at a rate of 1 mg/h. Transient hypotension was noted after the high-dose NTG bolus. The patient’s respiratory distress and oxygenation improved gradually and arterial blood gas analysis revealed improvement with pH 7.304, PaCO2 46.9 mm Hg, PaO2 64.4 mm Hg, and lactate 38 mg/dL (Table). The next day, chest X-ray revealed resolution of bilateral pulmonary congestion (Fig d). The patient was maintained in a negative fluid balance and fitted with a nasal cannula that was well tolerated. She was transferred to the general ward the next day and discharged from hospital on the third day after surgery.
 
Hysteroscopic myomectomy is a surgical treatment for submucosal myoma. During hysteroscopy, continuous fluid irrigation is required to distend the uterine cavity for optimal visualisation of the operative field. However, when intrauterine pressure exceeds mean arterial pressure, rapid intravasation via the venous sinuses may occur and absorption of excessive irrigation fluid may cause hypervolaemia and noncardiogenic pulmonary oedema. This phenomenon is termed operative hysteroscopy intravascular absorption syndrome with pathogenesis similar to that of TURP syndrome; as such, operative hysteroscopy intravascular absorption syndrome is also known as gynaecological TURP syndrome.1
 
Irrigation with electrolyte-free fluid in monopolar operative hysteroscopy may result in dilutional hyponatraemia and hypo-osmolality. Treatment of severe hyponatraemia-related neurological symptoms such as convulsion or cerebral oedema requires an infusion of 3% hypertonic saline solution. Use of a glycine-based solution can result in hyperammonaemia since ammonia is a by-product of glycine once absorbed and metabolised in the liver. In bipolar operative hysteroscopy, 0.9% normal saline is the commonly used irrigant, so there is no significant procedure-related hyponatraemia. Nonetheless in our patient, severe metabolic acidosis developed due to rapid absorption of chloride causing smaller plasma strong ion difference, leading to an increase in hydrogen ion, and therefore acidosis. There are no definitive diagnostic criteria for gynaecological TURP syndrome; the signs are varied and non-specific. Clinical symptoms following a hysteroscopic procedure in patients should be evaluated carefully to exclude or diagnose gynaecological TURP syndrome.
 
An intravenous NTG infusion is one of the treatments for acute pulmonary oedema. Nitro-glycerine produces nitric oxide that increases the formation of cyclic guanosine 3’,-5’-monophosphate.2 The increased intracellular cyclic guanosine 3’,-5’-monophosphate inhibits the influx of calcium into cells thereby decreasing intracellular calcium levels and causing vascular smooth muscle relaxation. This vasodilator effect on veins causes a decreased venous return, helps reduce cardiac preload and reduces pulmonary capillary hydrostatic pressure. The vasodilator effect on arteries in turn reduces systemic vascular resistance, helps reduce afterload and increases cardiac output. The main effect of NTG is on fluid redistribution of blood volume away from the lungs rather than on fluid removal per se.
 
To treat acute heart failure, the initial dose of NTG is 10 to 20 μg/min titrated to a total dose up to 200 μg/min until the desired haemodynamic effect is obtained.3 The main side-effects of NTG are hypotension and headache. The major concern of NTG therapy is resistance and tolerance under continuous infusion. In a previous study, intravenous bolus of high-dose NTG (2 mg) with repeated administration every 3 minutes, up to a total of 10 doses in treatment of severe decompensated heart failure, was associated with lower frequency of endotracheal intubation and intensive care unit admissions as well as few adverse events.4 The contra-indications to high-dose NTG bolus are severe aortic stenosis, hypertrophic obstructive cardiomyopathy, hypotension, and concurrent use of phosphodiesterase type 5 inhibitors.
 
Other strategies to treat acute pulmonary oedema include supplemental oxygen and/or ventilatory support, morphine, diuretics (eg, loop diuretic or thiazide), fluid restriction, inotropic agents in cases of co-morbid hypotension or hypoperfusion, and treatment of any underlying aetiologies.5 Non-invasive positive pressure ventilation improves pulmonary compliance and reduces atelectasis. This can reduce the work of breathing and decrease the need for endotracheal intubation.
 
The effect of NTG is rapid with an immediate peak effect and short half-life of 3 to 5 minutes. It offers greater efficacy, safety, and a faster onset of action than diuretics or morphine administered to cause rapid improvement of pulmonary congestion. In our case, the patient did not experience significant improvement after diuretics so an intravenous bolus of high-dose NTG was administered along with bi-level positive airway pressure support. As a result, while awaiting the fluid removal effect of diuretic therapy, high-dose NTG helped improve the respiratory distress and avoid an immediate need for intubation.
 
Our case findings suggest that high-dose NTG can be used to treat gynaecological TURP syndrome–induced acute pulmonary oedema and obviate the need for endotracheal intubation. As far as we know, this is the first case report of the application of high-dose NTG to treat gynaecological TURP syndrome. The success in this case may offer new insight for recommended treatment and further research.
 
References
1. Jackson S, Lampe G. Operative hysteroscopy intravascular absorption syndrome. West J Med 1995;162:53-4.
2. Ignarro LJ, Lippton H, Edwards JC, et al. Mechanism of vascular smooth muscle relaxation by organic nitrates, nitrites, nitroprusside and nitric oxide: evidence for the involvement of S-nitrosothiols as active intermediates. J Pharmacol Exp Ther 1981;218:739-49.
3. Ponikowski P, Voors AA, Anker SD, et al. 2016 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure: The Task Force for the diagnosis and treatment of acute and chronic heart failure of the European Society of Cardiology (ESC). Developed with the special contribution of the Heart Failure Association (HFA) of the ESC. Eur J Heart Fail 2016;18:891-975. Crossref
4. Levy P, Compton S, Welch R, et al. Treatment of severe decompensated heart failure with high-dose intravenous nitroglycerin: a feasibility and outcome analysis. Ann Emerg Med 2007;50:144-52. Crossref
5. Wilson SS, Kwiatkowski GM, Millis SR, Purakal JD, Mahajan AP, Levy PD. Use of nitroglycerin by bolus prevents intensive care unit admission in patients with acute hypertensive heart failure. Am J Emerg Med 2017;35:126-31. Crossref

Imaging findings of critically ill patients with COVID-19 pneumonia: a case series

Hong Kong Med J 2020 Jun;26(3):236–9  |  Epub 29 Apr 2020
© Hong Kong Academy of Medicine. CC BY-NC-ND 4.0
 
CASE REPORT
Imaging findings of critically ill patients with COVID-19 pneumonia: a case series
Stephanie C Woo, MB, BS# 1; KS Yung, MB, BS# 1;T Wong, FHKCR, FHKAM (Radiology)1; Ellen LM Yu, BSc, MSc2; SK Li, MB, ChB, FRCR1; HF Chan, FHKCR, FHKAM (Radiology)1; CH Chan, FHKCR, FHKAM (Radiology)1; YC Lee, FHKCR, FHKAM (Radiology)1; Jacky MC Chan, FHKCP, FHKAM (Medicine)3; WS Leung, FRCP, FHKAM (Medicine)3
1 Department of Radiology, Princess Margaret Hospital, Hong Kong
2 Clinical Research Centre, Princess Margaret Hospital, Hong Kong
3 Department of Medicine and Geriatrics, Princess Margaret Hospital, Hong Kong
# The first two authors contributed equally to the work
 
Corresponding author: Dr Stephanie C Woo (stephaniecheriwoo@gmail.com)
 
 Full paper in PDF
 
Introduction
Between 25 January 2020 and 7 February 2020, 22 patients admitted to Princess Margaret Hospital, Hong Kong had diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection confirmed by real-time reverse transcription polymerase chain reaction of nasopharyngeal aspirate and throat swab. Of them, three (13.6%) patients required intensive care unit (ICU) admission. Their clinical and laboratory data as well as computed tomography (CT) images were reviewed.
 
Herein, we review the findings from unenhanced CT scans of the thorax and serial chest radiographs in these three patients with coronavirus disease 2019 (COVID-19). The aim of the study was to provide insights into possible prognostic indicators of COVID-19 from an imaging perspective.
 
Case 1
In January 2020, a 68-year-old woman with travel history to Wuhan, China, was admitted to out unit presenting with fever, productive cough, and sore throat. Blood test results showed elevated C-reactive protein (CRP) level (72.9 mg/L, reference range <5 mg/L) and lactate dehydrogenase (LDH) level (295 U/L, reference range <250 U/L).
 
A CT scan of the thorax showed peripheral and subpleural involvement of ground-glass opacities (GGOs) and consolidations with interlobular septal thickening giving rise to a crazy-paving appearance. These abnormalities involved all lobes with a posterior predominance. No pleural effusion or mediastinal lymphadenopathy was evident (Fig 1a).
 

Figure 1. Case 1. A 68-year-old woman with travel history to Wuhan, China, presenting with fever, productive cough, and sore throat. (a) Computed tomography thorax showing interlobular septal thickening within the ground-glass opacities giving rise to the crazy-paving appearance (white arrowheads). (b) Chest radiograph on day 2 after admission showing patchy air-space opacities in bilateral lower zones without significant pleural effusion. (c) Chest radiograph on day 5 after admission showing progressive increase in bilateral air-space opacities involving bilateral upper and mid zones in addition to known lower zone opacities
 
Initial chest radiograph showed moderate bilateral air-space opacities with lower zonal predominance (Fig 1b). Subsequently, the patient’s condition deteriorated with worsening dyspnoea requiring increasing oxygen support. Serial chest radiographs showed progression of the air-space opacities (Fig 1c). However, costophrenic angles remained sharp despite disease progression, indicating the absence of significant pleural effusion. The patient was admitted to the ICU for intubation due to respiratory failure.
 
Case 2
In February 2020, a 64-year-old woman with travel history to Bangkok, Thailand, was admitted to out unit presenting with fever and dyspnoea, but no upper respiratory tract symptoms. Blood test results showed leucocytosis (12.6 × 109/L, reference range, 3.7-9.2 × 109/L) and elevated CRP (244 mg/L) and LDH (683 U/L) levels.
 
A CT scan of the thorax showed peripheral and subpleural involvement of GGOs and consolidations with interlobular septal thickening giving rise to a crazy-paving appearance. These abnormalities involved all lobes with a posterior predominance. No pleural effusion or mediastinal lymphadenopathy was evident (Fig 2a and b).
 

Figure 2. a) Case 2. A 64-year-old woman with travel history to Bangkok,Thailand, presenting with fever and dyspnoea, but no upper respiratory tract symptoms. Computed tomography (CT) of the thorax showing multiple patchy consolidations (black arrowheads) with subpleural involvement. No pleural effusion. (b) CT scan of the thorax showing bilateral ground-glass opacities (white arrows) and bronchial wall thickening (black arrow). (c) Chest radiograph on day 2 after admission showing patchy air-space opacities in bilateral mid and lower zones with no significant pleural effusion.The patient quickly deteriorated, requiring intubation. (d) Chest radiograph after intubation on day 3 after admission showing significant progression of the air-space opacities with lower zones more markedly affected than upper zones
 
Initial chest radiograph showed extensive air-space opacities with lower zonal predominance (Fig 2c). Subsequently, the patient’s condition deteriorated with worsening dyspnoea requiring increasing oxygen support. Serial chest radiographs showed progression of the air-space opacities (Fig 2d). However, costophrenic angles remained sharp despite disease progression, indicating the absence of significant pleural effusion.
 
The patient was admitted to the ICU for intubation due to respiratory distress and rapid deterioration.
 
Case 3
In January 2020, a 56-year-old man with travel history to Wuhan, China, was admitted to out unit presenting with fever and productive cough. Blood test results showed lymphocytopenia (0.7 × 109/L, reference range 1.1-2.9 × 109/L) and elevated CRP (33.2 mg/L) and LDH (266 U/L) levels.
 
A CT scan of the thorax showed peripheral and subpleural involvement of GGOs and consolidations. These abnormalities involved all lobes with a posterior predominance. No pleural effusion or mediastinal lymphadenopathy was evident (Fig 3a).
 

Figure 3. (a) Case 3. A 56-year-old man with travel history to Wuhan, China, was admitted to out unit presenting with fever and productive cough. Computed tomography of the thorax showing posterior predominance of ground-glass opacities and consolidation without pleural effusion. (b) Chest radiograph on day 4 after admission showing patchy air-space opacities in bilateral mid-to-lower zones with no significant pleural effusion. (c) Chest radiograph on day 8 after admission showing progressive increase in bilateral air-space opacities predominantly involving mid-to-lower zones
 
Initial chest radiograph showed mild to moderate air-space opacities with lower zonal predominance (Fig 3b). Subsequently, the patient’s condition deteriorated with worsening dyspnoea requiring increasing oxygen support. Serial chest radiographs showed progression of the air-space opacities (Fig 3c). However, costophrenic angles remained sharp despite disease progression, indicating the absence of significant pleural effusion.
 
The patient was admitted to the ICU for escalating need of high-flow nasal oxygen; intubation was not required.
 
Discussion
The current COVID-19 outbreak was first reported in Wuhan, China, in December 2019.1 On 23 January 2020, the first two confirmed cases of COVID-19 infection were reported in Hong Kong.2 In our patients, we observed a high frequency of occurrence of consolidations in addition to GGOs. The lesions showed bilateral peripheral involvement with initial lower zone predominance in all cases.
 
Multifocal peripheral GGOs in all of our patients are in keeping with findings of other recent studies on patients with COVID-19.3 4 This is also consistent with infections caused by other members of the betacoronavirus genus, including SARS-CoV5 and Middle East respiratory syndrome coronavirus (MERS-CoV).6 The presence of GGOs were reported to be up to 86% and 87% in the recently published reviews of patients with COVID-19 pneumonia.3 4 Different patterns of GGOs have been described in patients with COVID-19 pneumonia, with predominant posterior and peripheral lung distribution of GGOs being the most commonly described pattern.4 Such distribution is in line with observations of our patients but is less frequently reported in other non-coronavirus pneumonias.4
 
In contrast, consolidation is a much less common finding (ranging from 29% to 59%) in published studies of COVID-19 pneumonia.3 4 These studies included patients with varying disease severity. Since we only included critically ill patients requiring ICU admission, we postulate that the presence of consolidation can reflect a more aggressive disease, presenting a potential predictive feature for poorer prognosis. This observation is supported by a recent case review of COVID-19 pneumonia that found patients admitted to the ICU were more likely to have larger areas of bilateral consolidations on CT scans.3 On the contrary, GGOs are the main manifestation of patients who have milder disease.3 Pure GGOs without consolidations were reported in 77% of patients in another recent study.4 In addition, studies of MERS-CoV infection have also suggested that the presence of confluent consolidations is a radiological feature that might be predictive of poor prognosis.7 8
 
A limitation of the present case series is the limited sample size. Further studies with a larger sample size should be conducted to identify relevant radiological prognostic factors to confirm our initial findings.
 
Pleural effusion and mediastinal lymphadenopathy were absent in all of our cases. This is consistent with the low occurrence of these findings in other studies of patients with COVID-19 pneumonia. In one recent study, none of the patients were reported to have pleural effusion or mediastinal lymphadenopathy.3 In another study, pleural effusion and mediastinal lymphadenopathy were reported in 8% and 6% of patients, respectively.4 Previous studies of MERS-CoV infection found that pleural effusion may indicate poorer prognosis.7 8 However, this finding was absent in our patients.
 
All of our patients suffered from relatively rapid clinical deterioration with aggravation of air-space opacities on serial chest radiographs with GGOs and consolidations on CT scans of the thorax. Acute respiratory distress syndrome (ARDS) was found to be involved in a case series of patients with SARS-CoV infection.5 The authors of that case series concluded that the radiographic and CT findings of bilateral GGOs or consolidations and the rapid progression seen in some of their patients were consistent with ARDS, as autopsy findings of those deceased patients showed histological features identical to ARDS.5 This pathophysiology may also be applicable to COVID-19 pneumonia. This requires further verification by future studies with a larger sample size.
 
To conclude, we reported the radiological findings of three critically ill patients diagnosed with COVID-19 requiring ICU admission in Hong Kong. The presence of consolidations on CT of the thorax possibly indicates a more aggressive disease, and such observations are in line with the literature.
 
Author contributions
Concept or design: SC Woo, KS Yung, T Wong.
Acquisition of data: SC Woo, KS Yung, JMC Chan, WS Leung.
Analysis or interpretation of data: SC Woo, KS Yung, T Wong, ELM Yu, SK Li, HF Chan, CH Chan, YC Lee.
Drafting of the manuscript: SC Woo, KS Yung, T Wong, SK Li, HF Chan, CH Chan, YC Lee, JMC Chan, WS Leung.
Critical revision of the manuscript for important intellectual content: All authors.
 
All authors had full access to the data, contributed to the study, approved the final version for publication, and take responsibility for its accuracy and integrity.
 
Conflicts of interest
The authors have no conflicts of interest to disclose.
 
Funding/support
This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
 
Ethics approval
This study was approved by Kowloon West Cluster Research Ethics Committee (Ref EX-20-033(144-21)). The need for patient consent was waived by the Research Ethics Committee.
 
References
1. World Health Organization. Novel Coronavirus (2019- nCoV) Situation Report-1. 2020 Jan 20. Available from: https://www.who.int/docs/default-source/coronaviruse/situation-reports/20200121-sitrep-1-2019-ncov.pdf?sfvrsn=20a99c10_4. Accessed 3 Feb 2020.
2. Centre for Health Protection, Hong Kong SAR Government. CHP announces latest situations and measures on imported cases of novel coronavirus infection [press release]. 2020 January 23. Available from: https://www.info.gov.hk/gia/general/202001/23/P2020012300914.htm. Accessed 3 Feb 2020.
3. Kanne JP. Chest CT findings in 2019 novel coronavirus (2019-nCoV) infections from Wuhan, China: key points for the radiologist. Radiology 2020;295:16-7. Crossref
4. Song F, Shi N, Shan F, et al. Emerging 2019 novel coronavirus (2019-nCoV) pneumonia. Radiology 2020;295:210-7. Crossref
5. Müller NL, Ooi GC, Khong PL, Nicolaou S. Severe acute respiratory syndrome: radiographic and CT findings. AJR Am J Roentgenol 2003;181:3-8. Crossref
6. Ajlan AM, Ahyad RA, Jamjoom LG, Alherthy A, Madani TA. Middle East respiratory syndrome coronavirus (MERS-CoV) infection: chest CT findings. AJR Am J Roentgenol 2014;203:782-7. Crossref
7. Lee SE, Kim HL, Choi SM. A fatal case of Middle East respiratory syndrome corona virus infection in South Korea: chest radiography and CT findings. J Korean Soc Radiol 2016;74:407-11. Crossref
8. Das KM, Lee EY, Enani MA, et al. CT correlation with outcomes in 15 patients with acute Middle East respiratory syndrome coronavirus. AJR American J Roentgenol 2015;204:736-42. Crossref

Familial dysalbuminaemic hyperthyroxinaemia with discordant thyroid function test results: two case reports

Hong Kong Academy of Medicine. CC BY-NC-ND 4.0
 
CASE REPORTS
Familial dysalbuminaemic hyperthyroxinaemia with discordant thyroid function test results: two case reports
Nike KC Lau, MA(Cantab), MBChB (CUHK)1 †; Teresa KC Tsui, FHKCPath, FHKAM (Pathology)1; Jeffrey SS Kwok, FHKCPath, FHKAM (Pathology)1; Kitty KT Cheung, MRCP, FHKAM (Medicine)2; CC Chow, FHKCP, FHKAM (Medicine)2; CK Yeung, FHKCP, FHKAM (Medicine)3; YP Yuen, FHKCPath, FHKAM (Pathology)1 ‡
1 Department of Chemical Pathology, Prince of Wales Hospital, Hong Kong
2 Department of Medicine and Therapeutics, Prince of Wales Hospital, Hong Kong
3 Department of Medicine, Tseung Kwan O Hospital, Hong Kong
Currently affiliated with Chemical Pathology Laboratory, Department of Pathology, Princess Margaret Hospital, Hong Kong
Currently affiliated with Department of Pathology, Hong Kong Children's Hospital, Kowloon Bay, Hong Kong
 
Corresponding author: Dr Nike KC Lau (lkc416@ha.org.hk)
 
 Full paper in PDF
 
Case report
Discordant thyroid function test results are a commonly encountered diagnostic challenge. When the inverse log-linear relationship between thyroid stimulating hormone (TSH) and free thyroxine (fT4) is absent, a wide range of differential diagnoses should be considered. This requires the investigatory efforts of endocrinologists and chemical pathologists. We report the diagnostic journey of two Chinese patients with discordant thyroid function test due to familial dysalbuminaemic hyperthyroxinaemia (FDH) [OMIM #615999].
 
Patient 1 was a woman with no known family history of thyroid disorder. In 2003, she presented at age 49 years with palpitations and weight loss and was diagnosed with thyrotoxicosis (laboratory test results not available). She was prescribed an antithyroid drug for 18 months and her disease was in apparent remission. She presented again in December 2009, at age 55 years, with weight loss and anxiety. Total thyroxine tested in the private sector was elevated at 186.4 nmol/L (reference interval 58-155 nmol/L; platform not specified). She was commenced on carbimazole in view of her “relapse” and referred to endocrinology clinic for further management in March 2010. Her first paired TSH and fT4 (Roche Elecsys) results in April 2011 during carbimazole therapy revealed a discordant pattern with a normal TSH of 1.90 mIU/L and an elevated fT4 at 23.5 pmol/L (Table 1). Due to the apparent “persistent thyrotoxicosis”, she underwent radioactive iodine (RAI) thyroid ablation in May 2011, and carbimazole was stopped after her fT4 was “normalised”. Monitoring with fT4 only, her disease appeared to be in remission. Nonetheless her next paired thyroid function test in May 2013 showed elevated TSH 41.8 mIU/L and low fT4 11.9 pmol/L, consistent with frank post-RAI hypothyroidism. As a result, she was prescribed thyroxine replacement and her TSH was normalised (3.28 mIU/L) by June 2014. She was subsequently followed up in the general outpatient clinic. She was referred again to the endocrine clinic in June 2016 because both TSH and fT4 were elevated despite good compliance with thyroxine treatment. Withholding thyroxine replacement led to elevation of TSH (19.8 mIU/L) while fT4 (15.0 pmol/L) and free triiodothyronine (3.71 pmol/L) were within their respective reference intervals. Chemical pathologists were consulted for discordant thyroid function test results. This specimen was also tested using the Abbott Architect platform and showed similar thyroid function test results. Considering her TSH levels were never suppressed, TSH-dependent thyrotoxicosis was suspected although her serum alpha-subunit level was normal. She was then referred for genetic testing.
 

Table 1. Thyroid function test results (Roche Elecsys unless otherwise specified) of patient 1 demonstrating the diagnostic difficulty of familial dysalbuminaemic hyperthyroxinaemia compounded by the effects of antithyroid treatment
 
Patient 2 was a 34-year-old man who, in February 2004, presented with unintentional weight loss. His thyroid function test revealed normal TSH but elevated fT4 (laboratory test results not available). At follow-up examination, the patient’s TSH was re-checked (1.58 mIU/L; Roche Elecsys) but not his fT4, and test results for antithyroglobulin and antimicrosomal antibodies were negative. In view of such normal results, no further follow-up was arranged until the patient had another thyroid function test on Beckman Coulter Access. This was tested during a preoperative assessment in February 2017 and revealed an elevated fT4 (36.3 pmol/L) with a non-suppressed TSH (1.29 mIU/L). He was referred to the endocrinology clinic for further assessment. The patient reported a family history of thyroid disease: his mother had thyrotoxicosis treated with RAI, a maternal uncle had an unspecified thyroid illness, and an elder brother demonstrated a similar thyroid function test pattern. After discussion with chemical pathologists, subsequent samples were tested on other platforms and showed variable elevation of fT4 (Table 2). Among the four platforms, the degree of elevation in fT4 was greatest on Beckman Coulter Access (209%-224% of upper reference limit), followed by Roche Elecsys (155%). Siemens ADVIA Centaur (101%), and Abbott Architect (105%). The results from all four platforms were above the upper reference limit. Free triiodothyronine was also elevated on Beckman Coulter Access (108%), Abbott Architect (107%) and Siemens ADVIA Centaur (103%) platforms, although to a lesser degree. In view of the non-suppressed TSH level, the possibility of a TSH-secreting tumour was considered. Magnetic resonance imaging showed a 2-mm hypo-enhancing anterior pituitary lesion. Biochemical investigations showed normal serum alpha-subunit level and thyrotropin releasing hormone stimulation test. The patient was referred for genetic testing.
 

Table 2. Thyroid function test results of patient 2 on various platforms, without interfering effects of antithyroid treatment
 
Genetic testing for the THRB gene (OMIM *190160) was performed in both patients, in view of possible resistance to thyroid hormone syndrome (OMIM #188570). No pathogenic variant was detected by polymerase chain reaction and Sanger sequencing. Further testing in both patients for FDH targeting exon 7 of the ALB gene (OMIM *103600; Refseq NG_009291.1/NM_000477.6/NP_000468.1) showed heterozygous c.725G>A p.(Arg242His), a reported pathogenic variant in Chinese.1
 
Discussion
Familial dysalbuminaemic hyperthyroxinaemia is an autosomal dominant condition caused by variants of albumin, the gene product of ALB.2 The prevalence of FDH has been estimated to be 0.01% in Caucasian populations but much higher (1.0%-1.8%) in Hispanic populations.3 The prevalence is uncertain in East Asian populations. The variant found in our patients, c.725G>A, has an allele frequency of 0.005437% (1 in 18 392) in East Asian populations, according to the Genome Aggregation Database. However, FDH is less commonly observed than expected in Hong Kong. The under-recognition of FDH may be due to its asymptomatic nature, and the use of TSH without fT4 for screening of thyroid dysfunction. Our patients were identified only because of their apparent thyrotoxic symptoms and testing of fT4 on an affected platform. Although no treatment is required for FDH, it remains an important entity to recognise due to the potentially devastating complications of inappropriate treatment such as iatrogenic hypothyroidism as in patient 1, and adverse effects of antithyroid medications such as agranulocytosis. Family cascade screening and counselling should be considered to prevent undesirable misinterpretation and unnecessary treatment of other affected family members. It is strongly discouraged to treat either TSH or fT4 blindly, as is sometimes observed in clinical practice. Once these patients are treated with antithyroid drugs, often with only fT4 used for monitoring, there is an added risk to the development of frank hypothyroidism as the actual fT4 level is lower than the assayed value.
 
Here we discuss the approach to an elevated fT4 with a non-suppressed TSH in adults, which often requires the concerted efforts of a chemical pathologist and endocrinologist (Table 3). For a more comprehensive review of the general approach to discordant thyroid function test, the reader is advised to consult the excellent review by Koulouri et al.3 Possible differential diagnoses of an elevated fT4 with a non-suppressed TSH in an adult patient include assay interference (including FDH), drugs (such as thyroxine replacement, amiodarone, heparin), non-thyroidal illness (including acute psychiatric disorders), TSH-secreting pituitary adenoma, and resistance to thyroid hormone.3
 

Table 3. Approach for elevated fT4 with a non-suppressed TSH in an adult patient
 
First, clinical correlation of thyroid status with other clinical signs is essential in the interpretation of such thyroid function pattern. It would be sensible to exclude conditions that can be examined by a clinical or drug history, such as the effects of drug therapy, acute psychiatric episodes or non-thyroidal illness. A family history of thyroid disorder should be explored, because it may suggest an inherited condition, such as in patient 2.
 
Second, any previous thyroid function results should be reviewed. In patients with thyroid function test results incompatible with clinical features, at least one paired TSH and fT4 and/or free triiodothyronine should be performed to better detect discordant results. Patients who have previously shown a normal thyroid function pattern are less likely to have inherited conditions such as resistance to thyroid hormone or FDH. For FDH, it is important to note the assay platform used (hinted by the reference intervals provided), as a change of assay from one that is less affected by FDH to one that is prone to interference in FDH may give the clinician a false sense of an acquired condition. Moreover, the TSH level in patients with FDH should be normal unless due to thyroid-related treatment, or genuine pituitary or thyroid disease. It is often useful to plot the TSH and fT4 values and try to observe the reciprocal relationship between them. In FDH patients, such a relationship should be largely preserved even after antithyroid treatment, despite an upward shift in fT4 (Fig). This suggests the presence of a functional negative feedback system with the hypothalamus-pituitary-thyroid axis and is less likely to be a case of interference. Thyroxine replacement may further complicate the thyroid function test pattern if thyroxine is taken shortly before blood taking, although the usual thyroid function test requested for patients receiving thyroxine replacement is only TSH.
 

Figure. The 5th, 50th and 95th percentile of free thyroxine plotted against thyroid stimulating hormone using total patient data (in grey dots). The thyroid function test results of patient 1 (in black dots) demonstrated a largely preserved reciprocal relationship despite an upward shift in free thyroxine
 
Third, further investigations for possible assay interference should be discussed with chemical pathologists. In most clinical laboratories, thyroid function tests are performed using automated immunoassays that are prone to interference, for example by macro-TSH, biotin, anti-streptavidin antibodies, anti-ruthenium antibodies, thyroid hormone autoantibodies or heterophilic antibodies. Further testing such as assay comparison, serial dilution, antibody blocking agents, and polyethylene glycol precipitation may be considered to provide useful clues for possible interference.4 Often either the TSH or fT4 assay is affected. Nonetheless, in some cases such as biotin interference, both TSH and fT4 can be affected if they both use the biotin-streptavidin-based separation method in the assay. In patients with FDH, due to an increased binding affinity of thyroxine to albumin, total thyroxine is elevated, and to a lesser extent total triiodothyronine, although fT4 measured using equilibrium dialysis, which only minimally disrupts the equilibrium between the free and the bound portion of thyroxine, should be normal.4 Nevertheless, the presence of this albumin variant has been shown to lead to overestimation of fT4 levels in Roche Elecsys and Siemens Immulite (competitive one-step assays), whereas Abbott Architect (two-step assay) is less affected, because the thyroxine analogue does not come into contact with the variant albumin.5 Beckman Coulter Access, a two-step assay, is an exception as it also shows significant overestimation of fT4. The practical implication is that when FDH is suspected, one should examine the type of fT4 assay used, and repeat testing on a less affected platform.
 
Apart from the usual investigations for TSH-secreting pituitary adenoma such as magnetic resonance imaging of the pituitary and serum alpha subunit to TSH molar ratio, or genetic testing for resistance to thyroid hormone, further biochemical testing of the thyroid status of the patient should be considered. Tissue markers of thyroid hormone hyperfunction such as increased sex hormone-binding globulin, ferritin, pro-collagen-1-N-terminal peptide, and decreased cholesterol may provide additional evidence of a thyrotoxic state.6 The absence of these may suggest resistance to thyroid hormone, or assay interference. Further investigations such as serum thyroglobulin, thyroid antibodies (including anti-TSH receptor antibodies), thyroid scan, and ultrasonography may provide additional clues to the thyroid status in difficult cases. However, their use should be discussed with endocrinologists or relevant specialists to ensure optimal test utilisation and interpretation.
 
In summary, although both our patients ultimately received the correct diagnosis of FDH after collaboration between endocrinologists and chemical pathologists, the complications associated with misinterpretation and inappropriate treatment illustrate the importance of a good understanding of the analytical pitfalls of thyroid function test assays and proper follow-up investigations and management of discordant thyroid function test. Clinicians should be aware of the approach to discordant thyroid function, especially those who treat thyroid conditions.
 
Author contributions
Concept or design: All authors.
Acquisition of data: All authors.
Analysis or interpretation of data: NKC Lau, TKC Tsui, JSS Kwok.
Drafting of the article: NKC Lau, TKC Tsui, JSS Kwok.
Critical revision for important intellectual content: All authors.
 
All authors had full access to the data, contributed to the study, approved the final version for publication, and take responsibility for its accuracy and integrity.
 
Conflicts of interest
All authors have disclosed no conflicts of interest.
 
Acknowledgement
We would like to thank all laboratory and clinical staff who assisted in the cross-platform testing and management of the patients.
 
Funding/support
This case report received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
 
Ethics approval
Informed consent was obtained from all patients.
 
References
1. Tiu SC, Choi KL, Shek CC, Lau TC. A Chinese family with familial dysalbuminaemic hyperthyroxinaemia. Hong Kong Med J 2003;9:464-7.
2. Kragh-Hansen U, Galliano M, Minchiotti L. Clinical, genetic, and protein structural aspects of familial dysalbuminemic hyperthyroxinemia and hypertriiodothyroninemia. Front Endocrinol (Lausanne) 2017;8:297. Crossref
3. Koulouri O, Moran C, Halsall D, Chatterjee K, Gurnell M. Pitfalls in the measurement and interpretation of thyroid function tests. Best Pract Res Clin Endocrinol Metab 2013;27:745-62. Crossref
4. Favresse J, Burlacu MC, Maiter D, Gruson D. Interferences with thyroid function immunoassays: clinical implications and detection algorithm. Endocr Rev 2018;39:830-50. Crossref
5. Cartwright D, O’Shea P, Rajanayagam O, et al. Familial dysalbuminemic hyperthyroxinemia: a persistent diagnostic challenge. Clin Chem 2009;55:1044-6. Crossref
6. Singh BK, Yen PM. A clinician’s guide to understanding resistance to thyroid hormone due to receptor mutations in the TRα and TRβ isoforms. Clin Diabetes Endocrinol 2017;3:8. Crossref

Mitochondrial cardiomyopathy due to m.3243A>G mitochondrial DNA mutation presenting in late adulthood: a case report

Hong Kong Academy of Medicine. CC BY-NC-ND 4.0
 
CASE REPORTS
Mitochondrial cardiomyopathy due to m.3243A>G mitochondrial DNA mutation presenting in late adulthood: a case report
Elaine MC Chau, MB, BS, FRCP1; Edmond SK Ma, MD, FRCP2; Annie OO Chan, MD, FRCP1; TH Tsoi, MB, BS, FRCP1; WL Law, MS, FRCS3
1 Department of Medicine, Hong Kong Sanatorium & Hospital, Hong Kong
2 Department of Pathology, Hong Kong Sanatorium & Hospital, Hong Kong
3 Department of Surgery, Hong Kong Sanatorium & Hospital, Hong Kong
 
Corresponding author: Dr Elaine MC Chau (echau@hksh.com)
 
 Full paper in PDF
 
Case report
Mitochondrial cardiomyopathy usually presents in childhood and is estimated to occur in 20% to 40% of children with mitochondrial disease. However, it is a rare cause of cardiomyopathy in adults. We report a case of heart failure due to hypertrophic cardiomyopathy presenting in a 57-year-old female patient with intestinal pseudo-obstruction and bilateral sensorineural deafness. The constellation of diseased organs led to suspicion of underlying mitochondrial disease, subsequently confirmed by genetic mitochondrial DNA (mtDNA) testing that revealed the m.3243 A>G pathogenic variant in the MT-TL1 gene.
 
A 57-year-old female was referred for investigation of recent-onset congestive heart failure with cardiomegaly and bilateral pleural effusions on chest X-ray together with an elevated serum N-terminal pro-brain natriuretic peptide level of 241 pg/mL (normal <100 pg/mL). She presented with increasing abdominal distension and dyspnoea for 4 months. She had colonic pseudo-obstruction that did not resolve following repeated decompression and was referred for cardiac assessment with reference to fitness for colectomy under general anaesthesia. Apart from gradual hearing loss over the previous 8 years, she had been previously well. She suffered a miscarriage at age 23 years but subsequently gave birth to two apparently healthy daughters at age 32 and 36 years. Her main complaint over the previous year was constipation. There was no history of diabetes, muscle weakness, or visual problems. The older daughter was reported to have a squint since childhood, suggestive of ophthalmoplegia. There was no family history of any hearing, neurological, gastrointestinal or cardiac problems.
 
Clinically the patient was in distress and pain due to the grossly dilated abdomen from the colonic pseudo-obstruction (Fig 1). Positron emission tomography–computed tomography scan showed dilated bowel (up to 10 cm in diameter) from the caecum to the anus but no evidence of malignancy. Electrocardiogram showed sinus rhythm with left ventricular hypertrophy by voltage criteria and strain pattern. Echocardiogram showed left ventricular hypertrophy with mildly impaired left ventricular systolic function (ejection fraction 40%), diastolic dysfunction and a circumferential pericardial effusion (Fig 2). Computed tomography coronary angiogram was normal. Magnetic resonance imaging (MRI) heart revealed increased T1 mapping but no late gadolinium enhancement. Screening for amyloidosis was negative. Neurological assessment revealed no evidence of muscle weakness and the creatine kinase level was normal. Computed tomography brain showed dense calcification in bilateral lentiform nuclei and MRI brain was essentially normal.
 

Figure 1. Computed tomography abdomen showing grossly dilated large bowel
 

Figure 2. Two dimension-echocardiogram (parasternal long-axis view) showing left ventricular hypertrophy and a moderate amount of pericardial effusion
 
In view of pending rupture of the dilated colon (up to 10 cm), she underwent subtotal colectomy uneventfully. Histopathology of the resected colon showed no evidence of dysplasia or neoplasia. Blood was sent for mitochondrial disorder testing and showed a m.3243A>G mutation in the MT-TL1 gene, with approximately 10% heteroplasmy. The resected large bowel was micro-dissected for heteroplasmy determination of m.3243A>G by droplet digital polymerase chain reaction. The heteroplasmy levels for smooth muscle, epithelium and connective tissue of the large bowel were 77%, 66% and 46%, respectively.
 
Discussion
Mitochondrial DNA disease is a multi-system disorder that affects tissues with high energy demands such as the heart, brain, muscle, and endocrine system. It is caused by mutations in either mtDNA or nuclear DNA genes. Defects in mtDNA can be either point mutations or re-arrangements such as deletions or duplications. The m.3243A>G variant within the MT-TL1 gene (encoding the mitochondrial transfer RNA) is a point mutation and the most common heteroplasmic mtDNA disease genotype. This mutation accounts for approximately 80% of the MELAS phenotype (mitochondrial myopathy, encephalopathy, lactic acidosis, plus stroke-like episodes) that features mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes, and which this patient did not have. Other phenotypic variations associated with the m.3243A>G mutation include maternally inherited diabetes and deafness, ocular (eg, progressive external ophthalmoplegia), gastrointestinal, cardiac, and renal involvement. Most carriers of this mutation are asymptomatic due to mitochondrial heteroplasmy, implying the existence of two or more genomes within the same cell. Usually, the proportion of heteroplasmy needs to exceed a threshold level of 60% to 90% for the organ to be clinically affected. The onset and extent of clinical disease are determined by the mtDNA mutation load and threshold. In m.3243A>G mutation carriers, hypertrophic cardiomyopathy is found in about 18% of patients.1
 
In a small study of 10 m.3243A>G mutation carriers, the skeletal muscle mutation load appeared to correlate with the measures of early cardiac dysfunction on MRI, namely the torsion-to-endocardial strain ratio and radial thickening.2 Different patterns of cardiac involvement are associated with different mtDNA mutations. Although hypertrophic cardiomyopathy is frequently associated with mt-tRNA (transfer RNA) mutations such as the m.3243A>G mutation, restrictive cardiomyopathy is associated with the m.1555A>G mitochondrial ribosomal ribonucleic acid gene mutation. In children with Kearns-Sayre syndrome due to single, large-scale deletions in mtDNA, complete heart block is common.3 In our case, the heteroplasmy level within the different structures in the large bowel (46%-77%) was uniformly higher than in the blood (10%). This was consistent with the clinical presentation of pseudo-obstruction with the large bowel being the major organ involved.
 
Unfortunately, there is no cure for mitochondrial disease. Device therapy in the form of pacemakers and cardioverter-defibrillators may be required for heart block and ventricular arrhythmias associated with mitochondrial cardiomyopathy. Due to the complexity of mitochondrial disease, it is now recommended that affected patients be assessed using a validated semi-quantitative clinical rating scale, the Newcastle Mitochondrial Disease Adult Scale, to evaluate the different systems involved and to monitor response to treatment. Regular cardiovascular screening is recommended with electrocardiogram and echocardiogram performed at least every 2 years.4
 
Mitochondrial DNA is strictly maternally inherited, with only rare reports of paternal transmission. This may be due to a dilution effect since the sperm contain only 100 copies of mtDNA compared with 100 000 copies in the unfertilised egg and, secondly, there is elimination of sperm mtDNA in normal embryos. The m.3243 A>G mutation is usually transmitted from mother to offspring with rare reported cases of de novo mutation.5 Genetic counselling in mitochondrial disease may be difficult because of heteroplasmy, mitotic segregation, and mitochondrial bottleneck phenomenon. Phenotypic variations associated with m.3243A>G are due to a different percentage of mutation heteroplasmy in affected organs. It is known that an asymptomatic mother with a subclinical heteroplasmy level can give birth to an affected child with a higher heteroplasmy level. This is explained by the mitochondrial bottleneck theory, whereby redistribution of mtDNA to daughter cells during oocyte production and amplification of the redistributed mtDNA during oocyte development occurs. The unequal mitotic segregation of mtDNA during cell division and the reduction/amplification event leads to a random shift of mtDNA mutational load between generations. This is thought to be responsible for the variable levels of mutation heteroplasmy observed in affected offspring from mothers with pathogenic mtDNA mutations.
 
Conclusion
Mitochondrial cardiomyopathy is a rare cause of heart failure presenting in adulthood. Mitochondrial disease should be suspected when other organs or tissues are involved. Genetic testing is a powerful diagnostic tool. Severity and prognosis of mitochondrial disease depend on the concentration of heteroplasmy in the affected organs. Screening and follow-up cardiac assessment are recommended due to the progressive nature of cardiac involvement and risk of heart failure and arrhythmias as a cause of death in patients with mitochondrial mutation. Mitochondrial mutations are maternally inherited but the unique features of mitochondrial inheritance, namely mitotic segregation and mitochondrial bottleneck phenomenon, make predictions of inheritance a challenge. Genetic counselling should be offered to the families of an affected individual.
 
Author contributions
Concept or design: All authors.
Acquisition of data: EMC Chau, ESK Ma.
Analysis or interpretation of data: EMC Chau.
Drafting of the manuscript: EMC Chau.
Critical revision for important intellectual content: All authors.
 
The authors had contributed to the manuscript, approved the final version for publication, and take responsibility for its accuracy and integrity.
 
Conflict of interest
The authors have no conflicts of interest to disclose.
 
Funding/support
This case report received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
 
Ethics approval
The patient was treated in accordance with the Declaration of Helsinki. The patient provided informed consent for all procedures.
 
References
1. Pankuweit S, Richter A. Mitochondrial disorders with cardiac dysfunction: an under-reported aetiology with phenotypic heterogeneity. Eur Heart J 2015;36:2894-7. Crossref
2. Hollingsworth KG, Gorman GS, Trenell MI, et al. Cardiomyopathy is common in patients with the mitochondrial DNA m.3243A>G mutation and correlates with mutation load. Neuromuscul Disord 2012;22:592-6. Crossref
3. Bates MG, Bourke JP, Giordano C, d’Amati G, Turnbull DM, Taylor RM. Cardiac involvement in mitochondrial DNA disease: clinical spectrum, diagnosis, and management. Eur Heart J 2012;33:3023-3. Crossref
4. Schaefer AM, Phoenix C, Elson JL, McFarland R, Chinnery PF, Turnbull DM. Mitochondrial disease in adults: a scale to monitor progression and treatment. Neurology 2006;66:1932-4. Crossref
5. de Laat P, Janssen MC, Alston CL, Taylor RW, Rodenburg RJ, Smeitink JA. Three families with ‘de novo’ m.3243A>G mutation. BBA Clin 2016;6:19-24. Crossref

Kaposi’s sarcoma presenting with multiple cervical lymphadenopathies in a renal transplant recipient: a case report

© Hong Kong Academy of Medicine. CC BY-NC-ND 4.0
 
CASE REPORT
Kaposi’s sarcoma presenting with multiple cervical lymphadenopathies in a renal transplant recipient: a case report
TL Leung, MRCP (UK), LY Wong, FHKAM (Medicine), A Cheuk, FHKAM (Medicine)
Department of Medicine and Geriatrics, Princess Margaret Hospital, Laichikok, Hong Kong
 
Corresponding author: Dr TL Leung (aaronleungtl@hotmail.com)
 
 Full paper in PDF
 
Case report
A 57-year-old man underwent cadaveric renal transplantation in January 2018 and was prescribed mycophenolate mofetil, tacrolimus, and prednisolone as post-transplant immunosuppressive therapy. He developed multiple cervical lymphadenopathies at 6 months after transplantation. Fine needle aspiration cytology of the left submandibular lymph node, performed in the private sector, revealed only a hypocellular lesion. Considering the possibility of a post-transplantation lymphoproliferative disorder, excisional biopsy was arranged in our unit, but the patient defaulted from his appointment.
 
The patient attended the emergency department 9 months after transplantation complaining of shortness of breath. Physical examination on admission revealed generalised lymphadenopathy. Chest radiograph showed left lower, left middle, and right lower zone infiltrates. Despite the use of empirical piperacillin/tazobactam and withholding of mycophenolate mofetil, his condition deteriorated with worsening type one respiratory failure and increasing bilateral lung infiltrates on serial chest radiographs. Tacrolimus was discontinued. However, serial procalcitonin levels were undetectable. Computed tomography scan of the thorax suggested focal consolidative changes with diffuse cervical, axillary, mediastinal, hilar and abdominal lymphadenopathy (Fig 1). Biopsy of the groin and cervical lymph node showed spindle cell proliferation associated with surrounding vascular channels, red cell extravasation between spindle cells (Fig 2a), and positive human herpesvirus 8 (HHV-8) staining (Fig 2b). This confirmed the diagnosis of Kaposi’s sarcoma (KS). There was no plasmablastic histopathology to suggest the presence of multi-centric Castleman disease. Despite maximum supportive therapy with mechanical ventilation, empirical antimicrobials and antifungal treatment, his condition further deteriorated and he succumbed due to respiratory failure.
 

Figure 1. Computed tomography image of thorax showing diffuse mediastinal lymphadenopathy
 

Figure 2. Photomicrographs showing (a) low-power view of fascicles of spindle cells with uniform nuclei forming slit-like vascular spaces and (b) diffuse immunohistochemical staining for human herpesvirus 8
 
Discussion
Immunosuppressive therapy is known to increase the risk of infection and malignancy. In a study of incidence of malignancy among a cohort of Hong Kong kidney transplant recipients from 1972 to 2011, the most prevalent malignancies were non-Hodgkin’s lymphoma followed by colorectal cancer, lung cancer, kidney cancer, and non-melanoma skin cancer. Only five cases of KS were reported.1 The low incidence of KS may be due to the low prevalence of HHV-8 seroprevalence in Asia.2 There were only 68 reports of KS in Hong Kong between 1983 and 2016 according to the Hong Kong Cancer Registry. In this report, we describe a case of KS in a renal transplant recipient who presented with multiple cervical lymphadenopathies.
 
In the clinical context of multiple cervical lymphadenopathies in a post-transplant recipient, post-transplant lymphoproliferative disorder, and multi-centric Castleman disease are our initial top differential diagnoses. However, the histology of the lymph node of our patient did not suggest these diagnoses but KS. The clinical presentation of post-transplant KS can be divided into exclusive dermatological lesions or mucocutaneous lesions, with or without visceral involvement. Most patients present with single or multiple pigmented skin lesions with or without lower limb skin lymphoedema.3 4 5 6 7 Non-cutaneous KS is uncommon and was reported to account for only 5.4% of KS in a large AIDSassociated KS cohort.8 The gastrointestinal tract and the lungs are the most common sites for visceral involvement.4 7 Lymph node involvement is commonly associated with diffuse dermatological lesions or visceral involvement.7 9 Concomitant lymphoma is a possible but uncommon diagnosis for multiple cervical lymphadenopathies in a patient with KS.5 Overall, post-transplant KS that presents with multiple cervical lymphadenopathies without skin lesions is rare.
 
The first case of KS after renal transplantation was reported in 1969. Its prevalence has been reported as 0.4% to 5.3%, depending on the geographical prevalence of HHV-8 seropositivity.10 11 The average time to diagnosis has been reported as 12 to 39 months after transplantation.3 4 10 There is a male preponderance with a male-to-female ratio of 3:1.4 The 5-year survival rate is around 70%, although those with visceral involvement generally carry a poorer prognosis.12
 
There are no established guidelines for treatment of post-transplant KS so treatment often depends on clinical presentation. Tapering or withdrawal of immunosuppressants is the mainstay of therapy. Intralesional chemotherapy may be used for a single dermatological lesion. Systemic chemotherapy, such as liposomal anthracycline or taxanes, may be considered for widespread disease. Complete remission with immunosuppressant reduction or withdrawal has been reported as 50% to 60% and graft loss as 20% to 30% in the pre-mammalian target of rapamycin (mTOR) inhibitor era.7 10 Treatment with mTOR inhibitor, such as sirolimus, has gained recognition with its anti-angiogenic and anti-neoplastic activity, particularly among patients with an exclusive dermatological presentation. Three previous case series of 25 patients reported a 100% remission rate after switching from a calcineurin inhibitor to sirolimus, while two patients had graft loss due to causes other than rejection.3 5 6 Other case series have reported treatment failure with sirolimus. Visceral involvement and delay in switching from calcineurin inhibitor to mTOR inhibitor after diagnosis of KS may contribute to treatment failure.9 Further study is essential to determine the optimal treatment for post-transplant KS, especially for those with visceral involvement.
 
Conclusion
Post-transplant KS presenting with multiple cervical lymphadenopathies is rare and may signify an aggressive subtype. Withdrawing immunosuppressive therapy alone failed to salvage our patient. Further study is required to evaluate the potential of switching mycophenolate mofetil and calcineurin inhibitor to mTOR inhibitor to improve the prognosis for this subgroup of patients.
 
Author contributions
All authors contributed to the concept of the study, acquisition and analysis of the data, drafting of the manuscript, and critical revision of the manuscript for important intellectual content. All authors had full access to the data, contributed to the study, approved the final version for publication, and take responsibility for its accuracy and integrity.
 
Acknowledgement
We thank Dr Matthew KL Tong, Dr Hilda WH Chan, Dr Hon-lok Tang, and Dr Samuel KS Fung for their valuable opinions and supervision on writing the manuscript. We thank Dr Yuen-fun Mak for her expert guidance on pathology review.
 
Declaration
Part of the content about this case was presented in the Nephrology interhospital meeting in September 2019.
 
Conflict of interest
All authors have disclosed no conflicts of interest.
 
Funding/support
This case report received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
 
Ethical approval
The patient was treated in accordance with the Declaration of Helsinki. The patient provided informed consent for all procedures.
 
References
1. Cheung CY, Lam MF, Chu KH, et al. Malignancies after kidney transplantation: Hong Kong renal registry. Am J Transplant 2012;12:3039-46. Crossref
2. Zhang T, Shao X, Chen Y, et al. Human herpesvirus 8 seroprevalence, China. Emerg Infect Dis 2012;18:150-2. Crossref
3. Stallone G, Schena A, Infante B, et al. Sirolimus for Kaposi’s sarcoma in renal-transplant recipients. N Engl J Med 2005;352:1317-23. Crossref
4. Penn I. Sarcomas in organ allograft recipients. Transplantation 1995;60:1485-91. Crossref
5. Yaich S, Charfeddine K, Zaghdane S, et al. Sirolimus for the treatment of Kaposi Sarcoma after renal transplantation: a series of 10 cases. Transplant Proc 2012;44:2824-6. Crossref
6. Gutiérrez-Dalmau A, Sánchez-Fructuoso A, Sanz-Guajardo A, et al. Efficacy of conversion to sirolimus in posttransplantation Kaposi’s sarcoma. Transplant Proc 2005;37:3836-8. Crossref
7. Barete S, Calvez V, Mouquet C, et al. Clinical features and contribution of virological findings to the management of Kaposi sarcoma in organ-allograft recipients. Arch Dermatol 2000;136:1452-8. Crossref
8. Stebbing J, Mazhar D, Lewis R, et al. The presentation and survival of patients with non-cutaneous AIDS-associated Kaposi’s sarcoma. Ann Oncol 2006;17:503-6. Crossref
9. Lebbé C, Euvrard S, Barrou B, et al. Sirolimus conversion for patients with posttransplant Kaposi’s sarcoma. Am J Transplant 2006;6:2164-8. Crossref
10. Montagnino G, Bencini PL, Tarantino A, Caputo R, Ponticelli C. Clinical features and course of Kaposi’s sarcoma in kidney transplant patients: report of 13 cases. Am J Nephrol 1994;14:121-6. Crossref
11. Qunibi W, Akhtar M, Sheth K, et al. Kaposi’s sarcoma: the most common tumor after renal transplantation in Saudi Arabia. Am J Med 1988;84:225-32. Crossref
12. Woodle ES, Hanaway M, Buell J, et al. Kaposi sarcoma: an analysis of the US and international experiences from the Israel Penn International Transplant Tumor Registry. Transplant Proc 2001;33:3660-1. Crossref

Gastric synovial sarcoma: a case report and literature review

© Hong Kong Academy of Medicine. CC BY-NC-ND 4.0
 
CASE REPORT
Gastric synovial sarcoma: a case report and literature review
HK Wong, MB, BS1; Simon Law, MBBChir, FCSHK1; Robert Collins, MBBD (UNSW), FRCPA2
1 Department of Surgery, Queen Mary Hospital, The University of Hong Kong, Pokfulam, Hong Kong
2 Department of Pathology, Hong Kong Sanatorium & Hospital, Happy Valley, Hong Kong
 
Corresponding author: Prof Simon Law (slaw@hku.hk)
 
 Full paper in PDF
 
Case report
A 54-year-old Caucasian man presented with dyspepsia for 5 months with mild loss of weight. Endoscopic examination showed a 2-cm gastric ulcer with raised edges on the lesser curvature of the stomach. Endoscopic ultrasound demonstrated that the lesion involved the submucosa and muscularis propria, measuring 8 mm thick. Biopsy revealed, along with body-type mucosa, spindle cell tissue, 2 mm in diameter. The cells had indistinct cytoplasm with elongated nuclei showing mild enlargement, and variation in size and shape. The initial comprehensive immunohistochemical staining panel (AE1/3, CAM5.2, c-KIT, CD34, DOG1, actin, desmin, STAT6, synaptophysin, HMB45, CD45, and calretinin) gave no positive results while the Ki67 index was 5% to 10%. Computed tomography scan of the abdomen showed a 1.6-cm submucosal mass located at the gastric lesser curvature. There was no abnormal focal metabolic uptake in positron emission tomography scan. No hypermetabolic lymph node was found. The preoperative diagnosis was a submucosal spindle cell tumour.
 
Laparoscopic wedge resection of the gastric lesion was performed. Gross examination of the resected specimen showed gastric mucosa measuring 4 cm × 3.5 cm with submucosal tissue of 1 cm thick. There was an ulcerated lesion measuring 0.7 cm × 0.6 cm and 1.6 cm in maximal depth.
 
Microscopically, a dumbbell-shaped nodule was seen under the ulcer and extending through the muscularis propria to form a smooth nodule on the serosal aspect (Fig 1). Further immunohistochemical staining of the tumour cells was negative for cytokeratin (AE1/3, c-KIT, DOG1, CD31, CD34, desmin, actin, S-100, STAT6, ALK, calretinin, and HMB45. Ki-67 index was not high. The cells, however, showed positive staining for transducin- like enhancer protein 1 (TLE-1) upregulation (Fig 2) consistent with a diagnosis of synovial sarcoma and this was confirmed with fluorescence in situ hybridisation, which demonstrated a positive result for SS18 (synovial sarcoma) translocation. Six peritumoural lymph nodes and adjacent omentum showed no metastasis.
 

Figure 1. Photomicrograph showing gastric synovial sarcoma with haematoxylin and eosin method
 

Figure 2. Immunohistochemical stain showing transducin-like enhancer protein 1 upregulation consistent with gastric synovial sarcoma (× 20)
 
The patient recovered from his surgery without complications. He was followed up for 18 months after surgery with no signs of recurrence.
 
Discussion
Synovial sarcoma is a soft tissue sarcoma with common presentation in para-articular regions of the extremities although it is not related to synovium. It was first reported in 1893 and accounts for about 10% of all primary malignant soft tissue neoplasms.1 2 About 80% of synovial sarcomas are found in extremities, particularly the knee in the popliteal fossa, although they have also been reported in anatomical locations away from joints, including deep spaces in the head and neck, chest and abdominal wall, and visceral organs.3 4
 
Three histological subtypes of synovial sarcoma have been described: monophasic, biphasic, and poorly differentiated patterns. Monophasic synovial sarcoma is the most common subtype, in which the mesenchymal spindle cell component predominates. Biphasic synovial sarcoma has both a mesenchymal spindle cell component and an obvious epithelial component, representing 20% to 30% of synovial sarcomas.5 6 Poorly differentiated synovial sarcoma typically shows small round cell morphology and high mitotic activity, representing 15% to 25% of synovial sarcomas.7
 
Primary gastric synovial sarcomas are extremely rare, with only 31 cases reported in the English literature. Here we report a patient with primary gastric synovial sarcoma and published cases in the literature are reviewed.
 
Primary gastric synovial sarcoma is very rare, with the majority of malignant mesenchymal tumours in the stomach represented by malignant gastrointestinal stromal tumours (GISTs) and leiomyosarcoma. Synovial sarcoma has been reported to affect other parts of the gastrointestinal tract, including the oesophagus, duodenum, small bowel, ascending colon mesentery, liver, gastrocolic ligament, or omentum. However, the incidence of these tumours is very low, and few case reports are available in the literature. In 2000, Billings et al8 first reported two cases of primary synovial sarcoma in the gastroesophageal junction and stomach. In 2008, Makhlouf et al9 reported a series of 10 gastric synovial sarcomas, with mean age at diagnosis of 52 years. A recent published case was reported by Fuente et al10 in 2019. The most commonly reported clinical presentations of gastric synovial sarcomas are epigastric pain and anaemia.11 A clinical summary of the 36 cases of primary gastric synovial sarcoma, including our case, is shown in the Table.8 9 10 12 13 14 15 16 17 18 19 20 21 22 23
 

Table. Clinical features of 34 gastric synovial sarcomas
 
When a gastric spindle cell tumour is encountered, the differential diagnosis mainly focuses on other gastrointestinal mesenchymal tumours, such as GIST, leiomyoma, leiomyosarcoma, schwannoma and fibromatosis. Appropriate immunohistochemical staining is crucial in order to make a diagnosis of synovial sarcoma. Although TLE-1 is positive in the majority of synovial sarcomas, it is not specific for synovial sarcoma, as it can also be positive in other tumours such as endometrial stromal sarcoma, schwannoma, epithelioid sarcoma, solitary fibrous tumour, and rarely GISTs.
 
To confirm the diagnosis of synovial sarcoma, molecular analysis is essential. As many as 90% of synovial sarcomas possess a fusion between the SS18 gene on chromosome 18 and an SSX gene found on the X chromosome.11 This translocation, t(X;18), can be reliably detected on formalin-fixed paraffin-embedded tissue by polymerase chain reaction or fluorescence in situ hybridisation.24 25
 
Optimal treatment for gastric synovial sarcoma is surgical resection. There is no evidence that lymph node dissection (as in gastric adenocarcinoma) will benefit. Our patient underwent laparoscopic wedge resection of the gastric tumour and had an uneventful recovery. After surgery, we did not administer chemotherapy or radiotherapy as the resection margins were clear.
 
From the literature, all recurrences or disease-related deaths in gastric synovial sarcomas occurred in tumours >3 cm or those containing a poorly differentiated component; however, the prognosis of the disease is uncertain owing to the rare occurrence.
 
Important points to note
It is difficult to make a preoperative diagnosis of gastric synovial sarcoma based on endoscopic appearance only, as biopsies are usually negative. When sufficient tissue is obtained preoperatively, immunohistochemical staining can be applied. A panel of immunohistochemical stains should be utilised if the diagnosis is not apparent. When surgical resection is performed, the resected specimen should be saved for further evaluation.
 
When approaching a submucosal lesion identified on endoscopy with uncertain histological diagnosis, treatment usually is directed as if the lesion is a GIST, since this is most common. Local excision without lymphadenectomy is adequate, as in the current patient. Immunohistochemical staining and fluorescence in situ hybridisation are useful in differentiating gastric synovial sarcoma from other gastric spindle cell tumours.
 
The majority of recurrences in soft tissue sarcomas occur within the first 3 years of observation, and recurrence is rare in gastric synovial sarcoma. The assessment of recurrence risk, based on factors such as tumour grade and size, helps in determining a follow-up policy. According to the 2018 European Society for Medical Oncology Clinical Practice Guidelines26 on soft tissue and visceral sarcomas, the following approach is recommended: follow-up of surgically treated intermediate- or high-grade patients every 3 to 4 months in the first 2 to 3 years, then twice a year up to the fifth year, and once a year thereafter; low-grade sarcoma patients may be followed for local relapse every 4 to 6 months, with chest X-rays or computer tomography scan at longer intervals in the first 3 to 5 years, then annually.26 However, gastric synovial sarcomas are so rare that reliable guidelines cannot be recommended.
 
Conclusion
Gastric synovial sarcoma is extremely rare, and diagnosis requires specific immunohistochemical and molecular analysis. The presence of spindle cells usually reflects common mesenchymal tumour, yet the diagnosis of synovial sarcoma should also be considered when these cells are observed in gastric tumours and there is a discrepancy between the tumour morphology and the immunohistochemical stain results. The prognosis of these tumours is uncertain, given the rarity of the disease.
 
Author contributions
All authors had full access to the data, contributed to the study, approved the final version for publication, and take responsibility for its accuracy and integrity. S Law had the concept of the study, S Law and R Collins acquired the necessary data, all authors analysed and interpreted the data, all authors took part in drafting the manuscript as well as critically revised it for intellectual content.
 
Conflicts of interest
All authors have disclosed no conflicts of interest.
 
Funding/support
This case report received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
 
Ethics approval
The patient was treated in accordance with the Declaration of Helsinki. The patient provided informed consent for all procedures.
 
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