A 63-year-old man was referred to the memory clinic of Queen Mary Hospital in December 2021 for early-onset dementia. He had stepwise deterioration in cognitive function over the previous 6 months, especially in short-term memory, poor judgement, and spatial and temporal disorientation. His home environment was poor with rotten food. Physical examination revealed symmetrical parkinsonism. Montreal Cognitive Assessment Hong Kong version score was 10/30 (<2nd percentile). Vitamin B₁₂, folate and thyroid function tests were normal. A review of his medical history revealed three episodes of stroke since the age of 50 years. These episodes presented as left lower limb monoplegia, left-sided hemiplegia and slurring of speech 12 years, 8 years, and 1 year ago, respectively. Extensive workup including 24-hour Holter monitoring and transthoracic echocardiogram was unremarkable. He had hypertension and hyperlipidaemia and was prescribed amlodipine 5 mg and rosuvastatin 20 mg daily. His blood pressure was under control and the latest low-density lipoprotein was 1.7 mmol/L. A review of his computed tomography of the brain over the last 11 years showed a progressive increase in periventricular hypodensities (Fig 1). Brain magnetic resonance imaging (1 year previously) showed extensive periventricular hyperintensities and an old ischaemic insult over bilateral external capsules (Fig 2). Family history was notable for multiple first-degree relatives with young-onset stroke in their fifties and a suspected autosomal dominant inheritance pattern (Fig 3). Genetic testing of the neurogenic locus notch homolog protein 3 (NOTCH3) gene revealed a heterozygous mutation with a pathogenic variant (c.1630C>T, p.Arg544Cys), confirming the diagnosis of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). The family was referred for genetic counselling.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy is caused by cysteine-altering pathogenic variants in the NOTCH3 gene, with consequent vasculopathic changes, predominantly involving small penetrating arteries, arterioles, and brain capillaries.1 2 The mutation leads to an odd number of cysteine residues with deposition of osmiophilic material and progressive degeneration of vascular smooth muscle cells.1 2 The key to diagnosis includes a strong family history of young-onset stroke, an absence of strong vascular risk factors, and salient findings on brain magnetic resonance imaging, especially extensive white matter abnormalities and subcortical infarcts involving external capsules. Genetic testing for the NOTCH3 gene can be arranged after consultation with chemical pathologists in major public hospitals.3 4 The principle of management for symptomatic patients is similar to that of other patients with stroke, ie, antiplatelet therapy, lipid-lowering agents, and blood pressure control. There is no disease-modifying therapy currently available. Family members of affected individuals should be referred for genetic counselling with referral to tertiary centres for potential pre-implantation genetic testing to avoid transferring the mutation to offspring.5 There have been four other reported families with CADASIL in Hong Kong with different mutations. The mean age of symptom onset for index patients of these families was 51 years.3 4 The mutation in our patient has been commonly found in Fujian province and Taiwan, accounting for up to 14.5% to 70% of CADASIL cases.1

In summary, clinicians should obtain a detailed history and be alert to suspicious magnetic resonance imaging findings. Referral to chemical pathologists for genetic testing is key to the diagnosis of CADASIL.

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.

The authors have no conflicts of interest to disclose.

This study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

The patient was treated in accordance with the Declaration of Helsinki. Patient consent was obtained for all investigations.

1. Chen S, Ni W, Yin XZ, et al. Clinical features and mutation spectrum in Chinese patients with CADASIL: a multicenter retrospective study. CNS Neurosci Ther 2017;23:707-16. Crossref

2. Hu Y, Sun Q, Zhou Y, et al. NOTCH3 variants and genotype-phenotype features in Chinese CADASIL patients. Front Genet 2021;12:705284. Crossref

3. Au KM, Li HL, Sheng B, et al. A novel mutation (C271F) in the Notch3 gene in a Chinese man with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy. Clin Chim Acta 2007;376:229-32. Crossref

4. Hung LY, Ling TK, Lau NK, et al. Genetic diagnosis of CADASIL in three Hong Kong Chinese patients: a novel mutation within the intracellular domain of NOTCH3. J Clin Neurosci 2018;56:95-100. Crossref

5. Konialis C, Hagnefelt B, Kokkali G, Pantos C, Pangalos C. Pregnancy following pre-implantation genetic diagnosis of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). Prenat Diagn 2007;27:1079-83. Crossref

A 40-year-old female with unremarkable past health and no known family history of neurofibromatosis presented with a 3-year history of non-specific discomfort at the right submandibular region and upper neck. No facial nerve dysfunction was evident clinically. Ultrasound of the major salivary glands revealed a soft tissue nodule posterior to the right submandibular gland. Fine needle aspiration cytology findings were compatible with schwannoma. Subsequent magnetic resonance imaging (MRI) revealed a cluster of nodules within the deep lobe of the right parotid gland with a linear orientation. Further delineation with high-resolution MRI and neurography sequences with acquisition of double-echo steady state (DESS) [Fig 1] and post-contrast constructive interference in steady state (CISS) [Fig 2] sequences delineated these nodules arising eccentrically from the main trunk, inferior division and the marginal mandibular branch of the facial nerve, respectively. The patient continues with imaging surveillance while awaiting workup of underlying neurofibromatosis or schwannomatosis.

In the early era of MRI imaging, depiction of the extracranial intraparotid portion of the facial nerve was difficult, if not impossible, with conventional sequences. With advances in technology, higher resolution and newer imaging protocols allow clear delineation of intraparotid facial nerves. The use of high-resolution, three-dimensional and gradient echo–based techniques such as DESS1 and CISS2 allows clear delineation of the facial nerve from the parotid parenchyma and any adjacent facial nerve tumours, with a reasonable acquisition time of around 5 minutes. Both sequences have been proven useful in depicting the facial nerve and its branches,1 2 although there has not been any direct comparison of the efficacy of these sequences in facial nerve depiction. Nonetheless these two sequences are synergistic in the delineation of the facial nerve tributaries due to their differences in contrast characteristics. For DESS sequence, the facial nerve demonstrates positive contrast compared with the low-signal parotid gland; while in CISS, the facial nerve shows negative contrast compared with the high-signal parotid gland that is accentuated after contrast injection. The use of reconstruction techniques such as maximal intensity projection for DESS, or minimum intensity projection for CISS, can further improve visualisation of the peripheral nerve branches.

Dedicated magnetic resonance neurogram sequence for facial nerves is especially important in patients with salivary gland neoplasms, since facial nerve injury and consequent facial nerve weakness remain an important postoperative complication,3 and prior understanding of facial nerve anatomy is potentially helpful in reducing its incidence. It is also useful in predicting histology of nerve sheath tumours since schwannomas, as in our case, typically arise eccentrically from a nerve with displacement of its fascicles.4 Furthermore, such techniques can be applied to other extracranial nerves5 in the diagnosis of cranial neuropathies or in interventional planning for tumours in the head and neck region. Gradient echo–based DESS and CISS sequences partially overcome the problem of long acquisition time in conventional spin echo–based magnetic resonance neurogram; nonetheless images can be significantly compromised by susceptibility artefacts if adjacent implants are present. The latter remains a major obstacle that needs to be addressed.

Concept or design: All authors.
Acquisition of data: All authors.
Analysis or interpretation of data: HS Leung, JM Abrigo.
Drafting of the manuscript: HS Leung.
Critical revision of the manuscript for important intellectual content: JM Abrigo, EHL Lau, WCW Chu.

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.

All authors have disclosed no conflicts of interest.

The authors would like to acknowledge Mr Chi-kin Wong and Mr Chung-yee Cheung, radiographers of Gerald Choa Neuroscience Centre for their assistance in MRI scanning and devising MRI protocols.

This study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Ethics approval has been obtained from the Joint Chinese University of Hong Kong–New Territories East Cluster Clinical Research Ethics Committee (CREC Ref No.: 2021.639). Patient consent for publication was obtained.

1. Kim Y, Jeong HS, Kim HJ, Seong M, Kim Y, Kim ST. Three-dimensional double-echo steady-state with water excitation magnetic resonance imaging to localize the intraparotid facial nerve in patients with deep-seated parotid tumors. Neuroradiology 2021;63:731-9. Crossref

2. Guenette JP, Ben-Shlomo N, Jayender J, et al. MR imaging of the extracranial facial nerve with the CISS sequence. AJNR Am J Neuroradiol 2019;40:1954-9. Crossref

3. Jin H, Kim BY, Kim H, et al. Incidence of postoperative facial weakness in parotid tumor surgery: a tumor subsite analysis of 794 parotidectomies. BMC Surg 2019;19:199. Crossref

4. Soldatos T, Fisher S, Karri S, Ramzi A, Sharma R, Chhabra A. Advanced MR imaging of peripheral nerve sheath tumors including diffusion imaging. Semin Musculoskelet Radiol 2015;19:179-90. Crossref

5. Chhabra A, Bajaj G, Wadhwa V, et al. MR neurographic evaluation of facial and neck pain: normal and abnormal craniospinal nerves below the skull base. Radiographics 2018;38:1498-513. Crossref

Bilateral vertebral artery dissection (VAD) is often related to sudden mechanical injury of the arteries such as that following direct trauma or rotational forces. The natural course of bilateral VAD is variable, from recanalisation to fatal subarachnoid haemorrhage.1 We report a patient with bilateral VAD and favourable clinical course due to adequate carotid haemodynamic compensation despite progressive vertebrobasilar insufficiency.

In February 2007, a 42-year-old man presented with acute, stabbing neck pain, radiating to his occipital area and persisting for 5 days after performing yoga exercises while standing on his head. He showed no neurological deficit except for limited neck motion due to pain. Serial magnetic resonance angiography (MRA) 5, 12, and 19 days later revealed progressive bilateral VAD with consequent vertebrobasilar flow insufficiency (Fig 1). Cerebral angiography 25 days after this dissection revealed compensated retrograde filling of the basilar artery (Fig 2). The MRA taken 50 days after dissection showed much more aggravated steno-occlusive changes in the entire vertebrobasilar circulation (Fig 3). Unlike the progressive deterioration of vertebrobasilar circulation, the patient’s neck pain gradually resolved without neurological deficit.

Cerebral angiography performed after the first three MRA studies showed nearly complete occlusion of the vertebral arteries just distal to the bilateral posterior inferior cerebellar artery. This protected the patient against neurological deficit. It is unclear why the fourth MRA at 1 month later showed further deterioration of vertebra-basilar circulation. The potential explanation for this finding may be related to the increased compensatory carotid artery flow through the collateral circulation. The presence of adequate haemodynamic compensation from the carotid artery territory constitutes an important positive prognostic factor of the low-flow ischaemia in a patient with bilateral VAD.1 2

Funaki et al3 reported that serial MRA could be of great use to monitor restorative bilateral VAD haemodynamics. In contrast, our patient showed progressive deterioration of vertebrobasilar circulation. This suggests that the haemodynamic status of bilateral VAD can variably alter, so serial MRA can help monitor the progression of dissection in some patients.2

The present case suggests that the haemodynamics of bilateral VAD are variable and adequate haemodynamic compensation may constitute a positive prognostic factor.

Concept or design: BD Ku.
Acquisition of data: All authors.
Analysis or interpretation of data: All authors.
Drafting of the manuscript: BD Ku.
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.

The authors have disclosed no conflicts of interest.

The authors would like to thank Harrisco (www.harrisco.com) for the English language review.

This study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

This study was conducted in accordance with the principles outlined in the Declaration of Helsinki.

1. de Bray JM, Penisson-Besnier I, Dubas F, Emile J. Extracranial and intracranial vertebrobasilar dissections: diagnosis and prognosis. J Neurol Neurosurg Psychiatry 1997;63:46-51. Crossref

2. Bacci D, Valecchi D, Sgambati E, et al. Compensatory collateral circles in vertebral and carotid artery occlusion. Ital J Anat Embryol 2008;113:265-71.

3. Funaki T, Oshimoto T, Wataya T, et al. Bilateral vertebral artery dissection and its chronological changes detected by MR angiography: a case report [in Japanese]. No To Shinkei 2004;56:247-50.

A 70-year-old woman presented to our hospital for workup for chronic cough. A contrast computed tomography (CT) of the thorax and abdomen revealed an incidental finding of multilobulated soft tissue lesions in the abdomen along the left para-aortic region. The lesions measured up to 7.4 cm in diameter and demonstrated mild increased attenuation on pre-contrast images and vivid heterogenous enhancement on post-contrast study (Fig 1a and b). Appearance and location of these lesions raised concern about possible lymphadenopathy so fluorodeoxyglucose-18 positron emission tomography–CT was performed. The lesions demonstrated only mild metabolic activity (maximal standard uptake value=2.6) [Fig 1c]. They showed no interval change in appearance, and no other hypermetabolic lesion could be detected elsewhere. Tumour markers including alpha-fetoprotein, carcinoembryonic antigen, and cancer antigen 125 were not elevated.

The CT-guided biopsy of the para-aortic lesions subsequently showed cuboidal follicular cells arranged in architecture resembling thyroid parenchymal tissue (Fig 2). Immunostaining for thyroglobulin and thyroid transcription factor-1 were positive. There were no nuclear features of carcinoma.

Thyroid scintigraphy using technetium-99m pertechnetate showed intense radiotracer uptake over the corresponding para-aortic lesions (Fig 3). Findings were consistent with ectopic thyroid tissue. The presence of an orthotopic thyroid at its normal pretracheal position was demonstrated on CT and on technetium-99m scan (Fig 4). The patient’s thyroid function was normal.

Ectopic thyroid gland is a rare developmental abnormality with a prevalence of approximately 1 per 100 000 to 300 000 population.1 It results from aberrant embryogenesis of the gland during its migration from the foramen cecum at the posterior aspect of the tongue to its final pretracheal position. Frequent locations include its path of embryological descent along the midline of the neck, with a lingual thyroid at the base of the tongue being most common, accounting for up to 90% of reported cases.2 Other locations include the lateral neck and superior mediastinum. More distant locations such as subdiaphragmatic locations have also been reported but are exceedingly rare. To the best of the authors’ knowledge, this is the first report of ectopic thyroid tissue occurring at the para-aortic region of the abdomen, mimicking the appearance of lymphadenopathy on CT.

Thyroid scintigraphy is the most important and sensitive imaging tool to detect ectopic thyroid tissue. It also has the advantage of being able to demonstrate the presence or absence of an orthotopic thyroid gland. In patients with ectopic thyroid tissue, it is important to evaluate for the presence of orthotopic thyroid and thyroid function. Hypothyroidism may be present, particularly in those without a normal thyroid gland, and more common in patients with lingual ectopic thyroid.2 Ultrasound is also useful to locate and evaluate the orthotopic thyroid gland.

Computed tomography and magnetic resonance imaging are important adjuncts in evaluation. Ectopic thyroid tissue may show similar imaging characteristics to normal thyroid gland with high attenuation on non-contrast CT due to its high iodine content and vivid post-contrast enhancement. When ectopic thyroid tissue is found in a location not consistent with embryologic development, the possibility of malignant metastasis needs to be considered, occurring in 7% to 23% of patients.3 Biopsy is invaluable and the orthotopic gland should be evaluated for possible malignant change. Pathological changes that affect a normal thyroid including malignant change have been reported in ectopic tissues,1 and should be considered in the management and follow-up of ectopic thyroid tissue.

Concept or design: All authors.
Acquisition of data: CHK Wong, HL Tsui, CN Ling.
Analysis or interpretation of data: CHK Wong, HL Tsui, CN Ling.
Drafting of the manuscript: CHK Wong, HL Tsui, CN Ling.
Critical revision of the manuscript for important intellectual content: All authors.

All authors have disclosed no conflicts of interest.

This study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

The patient was treated in accordance with the Declaration of Helsinki. The patient provided written informed consent for all treatments and procedures and consent for publication.

1. Noussios G, Anagnostis P, Goulis DG, Lappas D, Natsis K. Ectopic thyroid tissue: anatomical, clinical, and surgical implications of a rare entity. Eur J Endocrinol 2011:165:375-82. Crossref

2. Guerra G, Cinelli M, Mesolella M, et al. Morphological, diagnostic and surgical features of ectopic thyroid gland: a review of literature. Int J Surg 2014;12 Suppl 1:S3-11. Crossref

3. Ballard D, Patel P, Schild SD, Ferzli G, Gordin E. Ectopic thyroid presenting as supraclavicular mass: a case report and literature review. J Clin Transl Endocrinol Case Rep 2018;10:17-20. Crossref

In September 2020, a 29-year-old woman presented to the emergency department with a 2-day history of upper abdominal pain. The patient had no history of recent trauma around the abdominal area. The patient’s vital signs were stable upon arrival but physical examination revealed tenderness over the right upper quadrant area. The patient reported moderate to heavy alcohol consumption (10-15 standard drinks per week). Laboratory findings revealed a white blood cell count of 3030/mm³, haemoglobin level 12.8 g/dL, and low platelet count of 34 000/mm³. The prothrombin time was mildly prolonged to 14.2 s. Elevated levels of liver enzymes, aspartate transaminase (113 U/L), direct bilirubin (6.18 mg/dL), and gamma-glutamyltransferase (350 U/L), were reported. Computed tomography (CT) scans showed a distended gallbladder with several gallstones and bile duct stones. Moreover, the intraluminal space of the gallbladder was filled with heterogeneous material, and extravasation of the contrast agent was suspected in the arterial phase (Fig 1). Emergency laparoscopic exploration was planned with a preoperative diagnosis of gallbladder haematoma. At the first laparoscope view, cirrhotic change to the liver with ascites and an oedematous gallbladder were evident (Fig 2a). The surgeon tried gallbladder decompression by needle aspiration and made a small opening to remove the blood but it was unsuccessful (Fig 2b). Laparoscopic cholecystectomy was successful without complications such as perforation (Fig 2c and d). Endoscopic retrograde cholangiopancreatography with endoscopic sphincterotomy was performed 5 days after the initial surgery and remnant common bile duct stones were removed. Pathological evaluation revealed a gallbladder haematoma with 30 to 40 gallstones (Fig 3). Moreover, venous vessels were remarkably dilated in the vicinity of the haemorrhagic site on CD31 immunostaining. The patient was discharged on postoperative day 10 with no complications.

The gallbladder is normally physiologically empty or filled with bile juice. Gallbladder haematoma is defined as filling of the gallbladder with blood. The definition can vary from gallbladder bleeding that comprises active bleeding inside the gallbladder to gallbladder haematoma when already-formed blood clots are evident. Haemorrhagic cholecystitis may be an appropriate term in cases of a gallbladder showing inflammation with blood. Reported risk factors for spontaneous bleeding include atherosclerosis or aneurysm, biliary malignancy, renal failure, cirrhosis, and coagulopathy, or anticoagulant medication.1 2 3 Moreover, abdominal blunt trauma can lead to gallbladder injury and cause gallbladder bleeding.3 Clinical manifestations of gallbladder haematoma similarly represent acute gallbladder disease.2 Upper abdominal pain is frequent due to distension of the gallbladder, and melena or haematemesis may also be present. In cases of cholecystitis, fever may develop, and laboratory study will demonstrate inflammation. The conventional radiological methods to evaluate gallbladder disease like ultrasonography or CT scan have diagnostic value.3 Ultrasonography may reveal a blood clot in the lumen with wall thickening and fluid accumulation around the gallbladder.2 In the CT scan, hyperdense blood and bile shadow with or without fluid level may be suspicious of gallbladder haematoma. Extravasation of contrast material into the lumen of the gallbladder during the arterial phase of contrast-enhanced CT is related to active bleeding.3,4 Surgical treatment produces superior results and the minimally invasive method of a laparoscopic approach has been widely adopted.1 3 Other endoscopic or percutaneous approaches for decompression may be considered before surgery.1 Gallbladder haematoma is associated with high morbidity and mortality. Delayed management potentially increases the risk of perforation and concomitant unfavourable outcomes.4 5

Concept or design: WY Nho.
Acquisition of data: D Je.
Analysis or interpretation of data: SK Kee.
Drafting of the manuscript: SK Kee.
Critical revision of the manuscript for important intellectual content: WY Nho.

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.

All authors have disclosed no conflicts of interest.

This study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

The study was reviewed and approved by the Institutional Review Board (IRB) of CHA Gumi Medical Center (GM20-11).

1. Leaning M. Surgical case report—acalculous hemorrhagic cholecystitis. J Surg Case Rep 2021;2021:rjab075. Crossref

2. Itagaki H, Katuhiko S. Gallbladder hemorrhage during orally administered edoxaban therapy: a case report. J Med Case Rep 2019;13:383. Crossref

3. Parekh J, Corvera CU. Hemorrhagic cholecystitis. Arch Surg 2010;145:202-4. Crossref

4. Kwon JN. Hemorrhagic cholecystitis: report of a case. Korean J Hepatobiliary Pancreat Surg 2012;16:120-2. Crossref

5. López V, Alconchel F. Hemorrhagic cholecystitis. Radiology 2018;289:316. Crossref