A 37-year-old woman presented to our neurosurgical centre in January 2003 with a 2-month history of progressive blurred vision and was found to have papilloedema. Magnetic resonance imaging (MRI) scan of the brain revealed a large left frontal parasagittal extra-axial dural-based tumour with homogenous gadolinium contrast-enhancement (6.3 cm × 4.3 cm × 3.7 cm) and Sindou grade II invasion (ie, into the lateral recess) into the junction of the anterior-to-middle third superior sagittal sinus (SSS). The patient underwent preoperative polyvinyl alcohol particle catheter tumour embolisation and a subsequent craniotomy was performed for Simpson’s grade III excision (macroscopic complete excision without resection of the tumour’s extra-dural extension into the SSS). The histological diagnosis was a World Health Organization (WHO) grade I meningothelial meningioma with a Ki-67 proliferation index of 5%. A 2-year surveillance MRI scan (Fig 1a) revealed an asymptomatic local recurrence with further invasion into the SSS (Sindou grade IV, ie, involvement of the roof and lateral wall). The patient was asymptomatic and reluctant to undergo further treatment, opting for regular observation of the lesion. A new MRI scan performed 11 years after the first operation revealed interval tumour growth with complete occlusion of the SSS (Sindou grade V) that was confirmed with MR venography (Fig 1b and c). A second craniotomy was performed in October 2014, 11 years after the first, but only subtotal excision could be achieved because of dense tumour adhesions to a large posterior frontal cortical draining vein. The histology remained that of a WHO grade I meningioma.

From a preoperative chest X-ray, performed in preparation for the patient’s second craniotomy, a new opacity in the right lower lobe was incidentally discovered. Computed tomography scan of the thorax revealed a single right lower lobe lung nodule (2.4 cm × 2.8 cm × 2.3 cm) with a well-defined border and vivid homogenous contrast enhancement (Fig 1d and e). Video-assisted thoracoscopic wedge resection of the right lower lobe was performed 8 weeks after the craniotomy with gross total excision achieved. The final pathological diagnosis was a metastatic WHO grade I meningioma with a Ki-67 proliferation index of 1% and clear margins (Fig 1f).

In view of residual intracranial disease, the patient underwent adjuvant fractionated radiotherapy (50.4 Gy). At 2 years after the second craniotomy, surveillance MRI brain scans and chest X-rays showed no detectable tumour.

Meningiomas are the most frequently diagnosed primary brain tumour in adults, accounting for 13% to 26% of all lesions.1 The population incidence is estimated to be four to six per 100 000 with a female:male ratio of 2:1. Despite this high prevalence, distant (extracranial) metastasis is extremely rare with fewer than 120 cases reported.1

The grading of meningiomas is principally determined by light microscopy of haematoxylin-eosin sections in accordance with WHO criteria. Grade I intracranial meningiomas comprise 80% of tumours and are generally considered benign, slow-growing lesions that have no demonstrable malignant behaviour such as distant metastasis. However, contrary to this belief, one third of meningiomas with distant metastases originate from grade I tumours with 31% identified incidentally.1 In contrast, grade III lesions, which demonstrate overt aggressive behaviour, represent only 1% of meningiomas and account for 40% of documented metastases.1 The true incidence of metastatic meningiomas is unknown, but given the frequent occurrence of grade I tumours, that metastatic lesions are often asymptomatic and that routine whole-body imaging is seldom performed, the stated figure of 0.1% is likely an underestimation.1 In our case, the interval between primary resection and metastasis detection was 11 years, considerably longer than the cited median duration of 58 months (range, 4 months to 15 years), reflecting the slow-growing nature of grade I tumours.1

Three quarters of metastatic WHO grade I meningiomas involve a single organ, primarily the lung (42%) followed by the spine (12%), bone (10%), liver (10%), and cervical lymph nodes (10%).1 Although conventional histological studies such as the Ki-67 proliferation index have failed to identify a subgroup of meningiomas predisposed to metastasis, loss of heterozygosity of 1p, 9p, 14q and 22q may be characteristic of these lesions.2 Clinical risk factors for metastasis include repeated surgery, local recurrence and invasion of the dural venous sinuses.1 The non-collapsible and valve-less nature of the dural venous sinuses, such as the SSS, may permit seeding of tumour cells into the internal jugular vein and subsequently into the pulmonary microcirculation, an indication that tumour location is pivotal in determining haematogenous metastasis.1 Parasagittal meningiomas, comprising 20% to 34% of lesions, are perhaps most susceptible because of their propensity to invade the SSS, technically hindering their complete resection.3 4 Our case illustrates the importance of treating the SSS infiltrating portion of these tumours, but there is little consensus on the appropriate management strategy. When the posterior SSS is patent, prohibiting its ligation and excision, some neurosurgeons prefer subtotal resection followed by adjuvant radiosurgery or radiotherapy.3 Others advocate the more technically demanding surgical approach of gross total resection with sinus reconstruction, to spare the patient the long-term adverse effects of irradiation.4 Both strategies offer comparable tumour control rates although multimodality treatment may be associated with fewer procedure-related complications.3

Bronchogenic carcinoma is the most important differential diagnosis to exclude in patients with pulmonary meningioma metastasis, but it is difficult to distinguish on computed tomography imaging. Meningioma metastases are usually single, non-calcified well-circumscribed lesions that may display strong homogenous contrast-enhancement.1 ¹¹¹Indium-octreotide imaging is useful in identifying meningiomas, exhibiting avid uptake, but its restricted availability limits its use.5 Excision of the pulmonary lesion is recommended to establish the diagnosis and in some instances the meningioma metastasis may manifest a more aggressive grading than the primary lesion warranting adjuvant radiotherapy.5 When multiple disseminated metastases preclude surgical excision, systemic treatments such as octreotide acetate or bevacizumab, an anti-angiogenic therapy directed against vascular-endothelial growth factor have shown some promise for tumour control.5 However, in a case series of patients with recurrent meningioma refractory to surgery, radiotherapy and chemotherapy, pulmonary metastasis was identified as an unfavourable prognostic factor for overall survival.5

Distant metastasis from a WHO grade I meningioma is a rare phenomenon and can occur more than a decade after the initial diagnosis of the primary tumour. This case demonstrates that, regardless of grading and especially when the patient is young, meningiomas that infiltrate the dural venous sinuses require proactive management, either by adjuvant irradiation or by gross total resection.

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.

Concept of study: PYM Woo, RSL Hung.
Acquisition of data: PYM Woo, RSL Hung.
Analysis of data: PYM Woo, RSL Hung, S Takemura.
Drafting of the article: PYM Woo, RSL Hung, S Takemura.
Critical revision for important intellectual content: All authors.

All authors have disclosed no conflicts of interest.

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

Ethics committee approval was waived because this is a case report and no personal identifying information was disclosed. A signed patient consent statement was obtained.

1. Surov A, Gottschling S, Bolz J, et al. Distant metastases in meningioma: an underestimated problem. J Neurooncol 2013;112:323-7. Crossref

2. Gladin CR, Salsano E, Menghi F, et al. Loss of heterozygosity studies in extracranial metastatic meningiomas. J Neurooncol 2007;85:81-5. Crossref

3. Gatterbauer B, Gevsek S, Höftberger R, et al. Multimodal treatment of parasagittal meningiomas: a single-center experience. J Neurosurg 2017;127:1249-56. Crossref

4. Ricci A, Di Vitantonio H, De Paulis D, et al. Parasagittal meningiomas: our surgical experience and the reconstruction technique of the superior sagittal sinus. Surg Neurol Int 2017;8:1. Crossref

5. Alexandru D, Glantz MJ, Kim L, Chamberlain MC, Bota DA. Pulmonary metastases in patients with recurrent, treatment-resistant meningioma: prognosis and identification by 111Indium-octreotide imaging. Cancer 2011;117:4506-11. Crossref

A 31-year-old man presented in December 2016 with a 1-day history of retained foreign body in the urinary bladder. He reported regular insertion of a commercially available silicone urethral instrument for autoerotism. He customarily evacuated the instrument by voiding but he had failed to do so on this occasion. There was no dysuria, haematuria, abdominal pain or fever. Laboratory parameters were within normal limits and no foreign body could be identified on X-ray. Flexible cystoscopy revealed an 18-cm length of soft tubing inside the urinary bladder (Fig 1a). Successful retrieval was achieved with endoscopic forceps. He was discharged home on the same day.

A 57-year-old man was admitted in January 2017 with a 6-week history of intermittent fever and right scrotal swelling. He had no lower urinary tract symptoms except for a yellowish urethral discharge. He revealed a history of regular per urethral insertion of self-customised plastic tubing with plastic beads inside the lumen for sexual gratification (Fig 1b and c). The patient cleaned the tubing with tap water after each use. Physical examination revealed a tender and swollen right testis with fluctuance, indicative of abscess formation. Serum white blood cell count was 15.1 × 10⁹/L. Drainage of scrotal abscess was performed and the patient was discharged home with a course of antibiotics.

A 55-year-old woman was admitted in May 2017 with a 1-day history of retained vibrator in the urinary bladder. The vibrator was inserted into her urethra during sexual activity with her husband. She complained of subsequent dysuria and haematuria. Serum white blood cell count was mildly elevated. X-ray revealed a 12.5-cm foreign body in the pelvic region (Fig 2). Retrieval of the vibrator via flexible cystoscopy failed owing to inadequate size and strength of the cystoscopic forceps. Semi-rigid ureteroscopy was used to locate the vibrator with Kocher forceps placed alongside for removal. Removal of the vibrator was achieved and the patient was discharged home with antibiotics.

Polyembolokoilamania refers to the act of inserting a foreign body into body orifices. Urethral polyembolokoilamania is not uncommon and several cases have been reported in the literature. Different types of foreign bodies have been reportedly introduced into the urethra, including electric wires, thermometers, hairpins, toothpicks, eyeglass rims, straws, pencils, paperclips, and fishhooks.1 2 Autoerotism is one of the most common reasons given for polyembolokoilamania, although others include curiosity, psychiatric illness, iatrogenic causes, and an attempt to relieve urinary symptoms.3 The prevalence of the condition is unknown and probably underreported owing to embarrassment of patients so a high index of suspicion and targeted history taking play an important role in correctly diagnosing the condition. There are reports suggesting the possible role of psychiatric assessment in revealing an underlying psychiatric disease and preventing repeated occurrences of foreign body insertion.4 Nonetheless psychiatric assessment is not considered mandatory for all patients. The prevalence of psychiatric diagnoses in this group of patients and the efficacy of psychiatric interventions are still largely unknown. There is no consensus on the role of psychiatric consultation for patients with urethral polyembolokoilamania.

Various complications may arise from insertion of foreign bodies per urethra including urinary tract infection, urethral injury and, most commonly, retained foreign body. The presentation of retained foreign body in the lower urinary tract varies widely although dysuria and haematuria are the most common presentation.3 5 The severity of the condition depends on the nature of the foreign body and, more importantly, time to medical attention. Early diagnosis and removal of the foreign body are of prime importance. In our case series, patients 1 and 3 sought early medical advice and experienced no complications. Late presentation may lead to complications such as recurrent urinary tract infection and urolithiasis or, less commonly, erosion of foreign body to adjacent organs.5 Presenting time is highly variable, ranging from hours to months.1 Delay in seeking medical consultation may stem from ignorance, psychiatric illness, or embarrassment.1

X-ray is often performed but is helpful in identifying only radio-opaque objects. Instead, flexible cystoscopy should be performed early for all patients with suspected retained foreign body in the lower urinary tract, in view of the relative simplicity and low risk of the procedure. Flexible cystourethroscopy can achieve accurate diagnosis and treatment simultaneously. A high success rate of 50% to 93% has been reported for endoscopic removal of foreign body.1 3 Computed tomography scan is indicated only in patients with peritonitis or suspected foreign body migration to adjacent organs.3

A surgical approach for retrieval of retained foreign body depends on the size, shape and location of the object. Simple measures, for example milking of the urethra, usually have a high success rate for expulsion of foreign body located in the distal penile urethra.3 Invasive approaches including open cystostomy and perineal urethrostomy have been reported when retrieving larger size, encrusted, or sharp objects after failed endoscopic manoeuvres.1 More complex procedures, including laparotomy and urinary diversion may be indicated for complicated cases. The surgical approach should be individualised.5

Insertion of foreign bodies into the urethra is predominantly reported in men. Palmer et al3 reported that 97% of their patients were men during their 15 years’ experience of managing self-insertion of urethral foreign bodies and six of their 27 patients had a recurrent history. This male-dominated phenomenon is also evidenced by the wide availability of male sexual urethral instruments in shops and online platforms. These instruments, namely urethral sounds and dilators, generally constitute a 15- to 20- cm-long stainless steel or silicone tube that is used for deep penetration to the level of the prostatic urethra. Deep prostate stimulation-associated orgasms are thought to be more intense than those with direct penile stimulation, and involve more pelvic muscle contractions.6 However, hygiene of the instrument is a concern as instrumentation without proper disinfection subjects a patient to further risk of infective complications.

In conclusion, insertion of a foreign body into the lower urinary tract for erotism is not uncommon, especially in men. Early diagnosis and endoscopic removal of the foreign body achieve a high success rate and should be considered the initial management. Delayed presentation may lead to complications that require further imaging and more complex surgical procedures.

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.

Concept or design: CL Cho.
Acquisition of data: CWH Mak.
Analysis or interpretation of data: CL Cho, CWH Mak.
Drafting of the article: CWH Mak, CL Cho.
Critical revision for important intellectual content: All authors.

The authors have disclosed no conflict of interest.

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

Verbal consent was obtained for the purpose of case study.

1. Rafique M. Intravesical foreign bodies: review and current management strategies. Urol J 2008;5:223-31.

2. Rahman NU, Elliott SP, McAninch JW. Self-inflicted male urethral foreign body insertion: endoscopic management and complications. BJU Int 2004;94:1051-3. Crossref

3. Palmer CJ, Houlihan M, Psutka SP, Ellis KA, Vidal P, Hollowell CM. Urethral foreign bodies: clinical presentation and management. Urology 2016;97:257-60. Crossref

4. Unruh BT, Nejad SH, Stern TW, Stern TA. Insertion of foreign bodies (polyembolokoilamania): underpinnings and management strategies. Prim Care Companion CNS Disord 2012;14(1). pii: PCC.11f01192. Crossref

5. Cury J, Coelho RF, Srougi M. Retroperitoneal migration of a self-inflicted ballpoint pen via the urethra. Int Braz J Urol 2006;32:193-5. Crossref

6. Alwaal A, Breyer BN, Lue TF. Normal male sexual function: emphasis on orgasm and ejaculation. Fertil Steril 2015;104:1051-60. Crossref

A 26-year-old woman presented to the emergency department of Queen Mary Hospital in August 2014 with fever and right otorrhea following extraction of her right lower third molar 5 days previously. Physical examination revealed right buccal swelling, limited mouth opening, and pus-like discharge in the right external auditory canal (EAC) exacerbated by mastication. There was no hearing loss or facial nerve palsy. Otoscopy revealed granulation tissue and pus arising from the anterior wall of the inner right EAC.

Contrast-enhanced computed tomography scan showed a right parapharyngeal rim enhancing collection (Fig 1) tracking into the right temporomandibular fossa. Enhancing soft tissue was seen at the inner one-third of the right EAC. A bony defect was present at its anterior wall, compatible with a persistent foramen tympanicum (also known as foramen of Huschke), allowing communication between the EAC and the temporomandibular fossa (Fig 2). Overall findings were compatible with right parapharyngeal abscess discharging via a persistent foramen tympanicum into the right EAC.

The patient was treated with a course of antibiotics in view of her stable condition and lack of airway compromise. The patient responded clinically and repeat computed tomography scan 1 week after initial presentation showed complete resolution of the right parapharyngeal abscess and enhancing soft tissue within the right EAC. Subsequent bacterial culture of the right ear discharge yielded Streptococcus anginosus, a common cause of oral infection.

Parapharyngeal abscesses are deep cervical infections with potential serious complications such as shock, mediastinitis, jugular vein thrombosis, upper airway obstruction, and death. Tonsillitis and odontogenic infection are the most common aetiologies. The clinical presentation typically involves fever, neck pain, odynophagia, neck oedema, and upper airway obstruction.1

Otorrhea is typically caused by external or middle ear pathologies such as otitis. Otorrhoea as a presenting symptom for a neck abscess is highly unusual. In our literature review, only two cases were found. Biron et al2 described a patient with a submandibular abscess that tracked into the ipsilateral external auditory meatus via the parapharyngeal and masticator spaces. Pepato et al3 reported a case of lower third molar infection presenting as purulent ear discharge, with persistent foramen tympanicum found in a follow-up cone-beam computed tomography study. The route of spread was postulated to be either via the Santorini fissures (the tiny defects in the anterior wall of the cartilaginous EAC) or via a persistent foramen tympanicum.

Persistent foramen tympanicum, first described by Emil Huschke in 1844, represents a failure of ossification of the tympanic part of the temporal bone and normally occurs from birth with completion by age 5 years. The foramen is located at the anteroinferior aspect of the EAC, just posterior to the temporomandibular joint. Incidence is quoted from 4.6% to 22.7% based on radiological and cadaveric studies.4

The majority of individuals with the foramen are asymptomatic although various complications have been reported. Most are benign, such as salivation from the ear during mastication and spontaneous herniation of the temporomandibular joint into the EAC leading to otalgia and tinnitus. Iatrogenic middle ear injury is possible when the foramen is inadvertently traversed during temporomandibular joint arthroscopy.5 It is possible that the lack of bony integrity reduces mechanical resistance to pathological processes, such as the spreading of parapharyngeal abscess in our case. Parotid pleomorphic adenomas have also been reported to herniate through the foramen to present as an EAC mass.

To the best of our knowledge, this is the first case to provide direct radiological evidence of persistent foramen tympanicum as a route for drainage leading to masticatory otorrhoea. It is important for doctors to be aware of the clinical presentation to permit diagnosis and subsequent treatment.

All authors contributed to the concept, image acquisition, image and data interpretation, manuscript drafting, and critical revision 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 research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Patient consent was obtained for the purpose of this case study.

1. Brito TP, Hazboun IM, Fernandes FL, et al. Deep neck abscesses: study of 101 cases. Braz J Otorhinolaryngol 2017;83:341-8. Crossref

2. Biron A, Halperin D, Sichel JY, Eliashar R. Deep neck abscess of dental origin draining through the external ear canal. Otolaryngol Head Neck Surg 2005;133:166-7. Crossref

3. Pepato AO, Yamaji MA, Sverzut CE, Trivellato AE. Lower third molar infection with purulent discharge through the external auditory meatus. Case report and review of literature. Int J Oral Maxillofac Surg 2012;41:380-3. Crossref

4. Akbulut N, Kursun S, Aksoy S, Kurt H, Orhan K. Evaluation of foramen tympanicum using cone-beam computed tomography in orthodontic malocclusions. J Craniofac Surg 2014;25:e105-9. Crossref

5. Nakasato T, Nakayama T, Kikuchi K et al. Spontaneous temporomandibular joint herniation into the external auditory canal through a persistent foramen tympanicum (Huschke): radiographic features. J Comput Assist Tomogr 2013;37:111-3. Crossref

Hashimoto’s encephalopathy (HE), also termed as steroid responsive encephalopathy associated with autoimmune thyroiditis, is a rare and highly variable clinical spectrum. The clinical presentation includes seizures, stroke-like episodes, cognitive decline, neuropsychiatric symptoms, and myoclonus.1 We report a rare and unusual case of HE in which there was a partial response to steroid therapy.

A 76-year-old man was admitted to the Department of Neurology of the Near East University Hospital, Cyprus, in October 2016 with the chief complaint of myoclonic jerks and walking difficulty for the past 6 weeks. The patient’s family had observed no significant cognitive or behavioural change. He did not experience any seizure. His medical history included hypertension and diabetes. On neurological examination he was alert and fully oriented. Motor weakness was noted at the left lower extremity with Babinski sign. He had myoclonus in all limbs and bilateral postural tremor, which was predominantly left sided. Magnetic resonance imaging (MRI) scan of the brain revealed widespread T2 hyperintensities mainly in the juxtacortical areas (Fig 1). Blood studies including complete blood count and electrolyte count; liver, renal and thyroid function tests; tumour markers; and paraneoplastic antibody analysis (anti-Hu, -Yo, -Ri, -Ma, -CV2) were all normal. Vasculitis markers including antinuclear antibodies, anti-ds DNA, anticardiolipin immunoglobulin (Ig) M, IgG antibodies, antiphosphatidylserine IgM, IgG antibodies, perinuclear antineutrophil cytoplasmic antibodies, cytoplasmic antineutrophil cytoplasmic antibodies, anti-La and anti-Ro antibodies, and rheumatoid factor were within normal limits. He tested negative for human immunodeficiency virus. His cognitive status worsened during his first week of hospitalisation and he rapidly developed delusions and aggressive behaviour. He was not able to cooperate with the neurocognitive assessment. Electroencephalogram showed 5 to 6 Hz diffuse slow-wave activity without any epileptiform discharge (Fig 2). Cerebrospinal fluid (CSF) analysis showed a very high protein content (1.95 g/L). The CSF/serum glucose ratio was normal. Cerebrospinal fluid investigation and culture was negative, excluding central nervous system infection. Whole-body positron emission tomography was performed to exclude paraneoplastic processes and the result was normal. Consequently, steroid-responsive encephalopathy and associated autoimmune thyroiditis was suspected, and antithyroglobulin antibody (anti-TG-Ab) and antithyroperoxidase antibody (anti-TPO-Ab) levels were studied. Serum level of both was increased (431 IU/mL and 40 IU/mL respectively). He was not taking any medication (eg, lithium, amiodarone, etc) that could account for the positivity of thyroid antibodies. Thyroid ultrasonography did not show any pathological findings. Intravenous pulse steroid treatment (IVPS, methylprednisolone 1 g/day) was started. Myoclonus resolved on the fourth day of treatment. Because the cognitive status of the patient was not adequately changed, IVPS was extended to 10 days. A partial response was obtained in cognition and Mini-Mental State Examination score was 11/30 after IVPS. Another electroencephalogram showed mild improvement. Consequently, oral methylprednisolone was continued at a dosage of 1 mg/kg/day. Afterwards, intravenous Ig treatment was given at a dose of 0.4 g/kg for 5 days. No additional improvement was seen. Lumbar puncture and thyroid autoantibody testing were repeated. The anti-TPO-Ab and anti-TG-Ab levels were normalised, and CSF was acellular at that time and protein content decreased (1.45 g/L). Azathioprine 100 mg/day was gradually added to his treatment. The patient was discharged from the hospital with oral steroid and azathioprine treatment. His neurological status was stable. He died 3 months later due to a lung infection.

The clinical findings, CSF analysis, and MRI of our patient were compatible with HE. The challenging conditions we faced were the lack of prominent cognitive or psychiatric change at the beginning and normal thyroid functions. The differential diagnosis included vasculitis, paraneoplastic limbic encephalitis, and Creutzfeldt-Jakob disease (CJD). The MRI was very helpful for differential diagnosis. The pattern of isolated cortical hyperintensity with concomitant combined cortical and deep grey matter (basal ganglia) hyperintensity on fluid attenuation inversion recovery along with restricted diffusion can differentiate CJD from other rapidly progressive dementias with a high sensitivity and specificity.2 Because the consecutive diffusion-weighted images of the patient were not compatible with CJD, 14-3-3 assay in the CSF was not studied. In addition, it is not specific for CJD and its positivity is also reported in HE.3 The laboratory and imaging findings were not compatible with limbic encephalitis. We assessed his objective clinical recovery (dramatic disappearance of myoclonus and partial cognitive-behavioural improvement) following pulse steroid therapy. Response to treatment may also exclude the diagnosis of CJD.

The pathophysiology of HE is not well understood. Autoimmune cerebral vasculitis and antibody-mediated neuronal reaction are the most accepted mechanisms. Most patients are euthyroid at the time of diagnosis.4 Antithyroperoxidase antibody is known as a positive predictor of responsiveness to steroid therapy and higher titres are associated with a more favourable outcome.5 Most cases in the literature treated with steroids make a complete recovery.5 Since it is a rare condition, the optimum treatment for steroid-resistant cases is unknown. Response to intravenous Ig or plasmapheresis treatments in steroid non-responsive cases has also been reported.5 Despite the normalisation of anti-TPO-Ab and anti-TG-Ab levels and somewhat improved inflammatory findings of CSF after treatment, we observed a complete response in myoclonus and only a partial improvement in cognition in our patient. This supports the hypothesis that thyroid autoantibodies are not the only pathogenic mechanism in HE. Other causes, the role of the thyroid gland, and other antibodies should be clarified by future studies.

Concept or design: B Kaymakamzade, S Ertugrul Mut.
Acquisition of data: H Özkayalar, A Eker, S Ertugrul Mut.
Analysis or interpretation of data: B Kaymakamzade.
Drafting of the manuscript: All authors.
Critical revision for important intellectual content: S Ertugrul Mut, B Kaymakamzade.

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.

We thank Dr Mustafa Canatan and Dr Fehim Türktan for their contribution to the editing of the manuscript.

All authors have disclosed no conflicts of interest.

This research 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. The patient provided written informed consent.

1. Mocellin R, Walterfang M, Velakoulis D. Hashimoto’s encephalopathy: epidemiology, pathogenesis and management. CNS Drugs 2007;21:799-811. Crossref

2. Vitali P, Maccagnano E, Caverzasi E, et al. Diffusion-weighted MRI hyperintensity patterns differentiate CJD from other rapid dementias. Neurology 2011;76:1711-9. Crossref

3. Hernández Echebarría LE, Saiz A, et al. Detection of 14-3-3 protein in the CSF of a patient with Hashimoto’s encephalopathy. Neurology 2000;54:1539-40. Crossref

4. Oide T, Tokuda T, Yazaki M, et al. Anti-neuronal autoantibody in Hashimoto’s encephalopathy: neuropathological, immunohistochemical, and biochemical analysis of two patients. J Neurol Sci 2004;217:7-12. Crossref

5. Litmeier S, Prüss H, Witsch E, Witsch J. Initial serum thyroid peroxidase antibodies and long-term outcomes in SREAT. Acta Neurol Scand 2016;134:452-7. Crossref

A 46-year-old man presented to the Department of Orthopaedics and Traumatology, Pamela Youde Nethersole Eastern Hospital in February 2004 with a 3-month history of self-detected left thigh mass. It was of spontaneous onset with no history of trauma, associated pain, weakness, or numbness. The patient had full range of movement and no lymphadenopathy was noted. Magnetic resonance imaging (MRI) [Fig 1] revealed a large area of infiltrative soft-tissue thickening at the medial aspect of the left distal thigh and involved the subcutaneous layer. The lesion measured 8.4 × 3.4 × 11.2 cm (anteroposterior × transverse × longitudinal) and was characterised by T1-weighted (T1W) hypointense to isointense and T2-weighted (T2W) fat-suppressed hyperintense signals with internal heterogeneity. Internal foci of hypointensity in the T2W fat-suppressed images were noted. An internal reticular pattern of septal thickening was also found. There was enhancement after gadolinium contrast administration. The margin of the lesion was well delineated from the underlying vastus medialis and sartorius muscles with no features of muscular invasion or destruction. The knee joint was unremarkable and bone marrow signal was normal. The neurovascular bundle was also intact. Overall features were non-specific for either inflammatory or neoplastic pathology.

Microscopic examination of an incisional biopsy over the left vastus medialis with a wedge of skin and subcutaneous tissue revealed infiltrate in the subcutis and to a lesser extent the deep dermis. The infiltrate consisted of lymphocytes and a low number of plasma cells. Immunohistochemical stains showed mainly T-cells and some B-cells. Occasional areas with aggregates of paler histiocytic cells were present and suggested granuloma formation. Stains for acid-fast bacilli and fungus were negative. The paler histiocytic cells were S100-positive and showed lymphophagocytosis (Fig 2). Molecular study by polymerase chain reaction showed no clonal T-cell proliferation. The overall features were suggestive of Rosai-Dorfman disease (RDD).

Radical excision of the lesion was performed subsequently and included the epimysium of the gracilis, sartorius and aponeurosis of the vastus medialis. The excision margin in the radial excision of the lesion was 2 cm. Microscopic examination revealed that the mass in the subcutis was composed of nodules or aggregates of lymphohistiocytic cells separated by areas of fibrosis. The cellular aggregates were composed of dark areas with plasma cells and lymphocytes and pale areas with clusters of histiocytes. The histiocytes showed round vesicular nuclei, distinct nucleoli, and abundant foamy cytoplasm with presence of emperipolesis (phagocytosis of plasma cells and lymphocytes). The histiocytes showed positive immunostaining for S100. Special stains for acid-fast bacilli and fungus were again negative. The overall features were consistent with RDD. The resection margins were unremarkable. The patient recovered well postoperatively.

Eight years after the operation, the patient detected a nodular swelling over the inferior margin of the surgical site. Serial MRI showed a static nodular T1W hypointense, and T2W isointense to mildly hyperintense soft-tissue lesion with contrast enhancement, measuring approximately 8 mm in diameter (Fig 3). Features could represent postoperative change or tumour recurrence. The patient was otherwise asymptomatic and he opted for follow-up scans to monitor the lesion instead of surgical excision.

Rosai-Dorfman disease is also known as sinus histiocytosis with massive lymphadenopathy and was first described by Rosai and Dorfman in 1969.1 It is a rare non-malignant histiocytic proliferative disorder. Although the disease may develop at any age, it is more common in young adults with a mean age of onset of 20 years and a slight male predominance (1.4:1).2 3

The aetiology of RDD is unknown, although previous studies have attempted to relate RDD to infectious agents including Epstein-Barr virus, human herpesvirus 6, herpes simplex virus, Brucella, Klebsiella rhinoscleromatis, and Nocardia.4 The disease involves a wide distribution and can affect a multitude of organ systems, including nodal involvement and extranodal involvement. The majority of patients present with painless massive cervical lymphadenopathy. Most patients have a complete and spontaneous remission, but some may experience recurrent or persistent albeit stable lymphadenopathy. In rare cases, the disease may follow an aggressive course and be fatal.

Pure cutaneous RDD is a distinct clinical entity that has an older age of onset (median 43.5 years) and a male-to-female ratio of 1:2.3 In contrast to systemic RDD that is commonly seen in blacks and rarely reported in Asians, most patients with purely cutaneous RDD are Asians or whites. The lesion remains localised to the skin even after long-term follow-up.5

Histologically, RDD is characterised by sheets of large pale histiocytes with large, round, vesicular nuclei. Phagocytosis of lymphoid cells or neutrophils by histiocytes may be found (“emperipolesis”). Immunohistochemical stains are useful when diagnosing RDD and the most consistent and reliable phenotype for RDD is S100 positive and CD1a negative.

Relative to the wide disease spectrum, there are variable radiographic features. Although no specific imaging characteristics allow differentiation of lymphadenopathy in RDD from the myriad other disease processes, massive painless bilateral cervical lymph node enlargement, particularly when it occurs in children and adolescents, should prompt consideration of RDD as a differential diagnosis. Nodal involvement may be evidenced as lymphadenopathy. In computed tomography scan of the sinuses and brain, polypoid masses, mucosal thickening, soft-tissue lesion of the paranasal sinuses or nasal cavity with or without associated osseous erosion can be seen. Features of brain involvement include a hyperattenuating meningeal-based mass showing contrast enhancement or parenchymal oedema surrounding the lesion. In MRI of the sinuses and brain, sinus lesions may also demonstrate hypointensity on T2W images. Meningeal-based mass lesions may demonstrate T1W isointensity to grey matter, T2W hyperintensity to grey matter and homogeneous contrast enhancement.6 Gallium scanning may show increased uptake and increased metabolism with fluorodeoxyglucose positron emission tomography. The differential diagnosis is broad and includes infectious (granulomatous) disease, Wegener’s granulomatosis, other histiocytosis, Hodgkin’s and non-Hodgkin’s lymphoma, and fibroinflammatory lesions. In general, RDD does not show bone or soft-tissue destruction as in cases of Wegener’s granulomatosis and T-cell lymphoma.

Rosai-Dorfman disease usually follows a benign and self-limiting course with treatment largely targeted at controlling local manifestations. Surgical options may be warranted for symptomatic control.

All authors contributed to the concept or design, acquisition of data, analysis or interpretation of data, drafting of the manuscript, and critical revision 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.

All authors have disclosed no conflicts of interest.

This research 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 Declaration of Helsinki. The patient provided written informed consent.

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