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.

1. Rosai J, Dorfman RF. Sinus histiocytosis with massive lymphadenopathy. A newly recognized benign clinical pathologic entity. Arch Pathol 1969;87:63-70.

2. Annessi G, Giannetti A. Purely cutaneous Rosai-Dorfman disease. Br J Dermatol 1996;134:749-53. Crossref

3. Brenn T, Calonje E, Granter SR, et al. Cutaneous Rosai-Dorfman disease is a distinct clinical entity. Am J Dermatopathol 2002;24:385-91. Crossref

4. Lu CI, Kuo TT, Wong WR, Hong HS. Clinical and histopathologic spectrum of cutaneous Rosai-Dorfman disease in Taiwan. J Am Acad Dermatol 2004;51:931-9. Crossref

5. Farooq U, Chacon A, Vincek V, Elgart GW. Purely cutaneous Rosai-Dorfman disease with immunohistochemistry. Indian J Dermatol 2013;58:447-50. Crossref

6. Symss NP, Cugati G, Vasudevan MC, Ramamurthi R, Pande A. Intracranial Rosai Dorfman disease: report of three cases and literature review. Asian J Neurosurg 2010;5:19-30.

Solitary lung nodules of <3 cm in diameter within the lung parenchyma and with no other abnormalities are often picked up incidentally during routine radiographic imaging. The incidence of cancer for such nodules has been estimated to be 10% to 70%. Management strategy depends on the clinical probability of cancer; nodule size, features, and growth rate ascertained by radiology; and the surgical risk to the patient. We report a case of such a nodule revealed by radiology and suspicious for malignancy. Subsequent excision and pathological examination revealed unexpected findings.

The index patient was a 61-year-old Chinese man from Northern China with history of laryngeal cancer treated successfully by local surgery and radiotherapy 6 years prior to present admission. Routine chest computed tomography (CT) scan revealed a peripheral lung nodule 9 mm in diameter in the right lower lobe. Follow-up CT scan 1 year later revealed minimal increase in size to 10 mm and the patient was referred to the Department of Thoracic Surgery, University of Hong Kong–Shenzhen Hospital in November 2015 for further treatment. The patient was a former chronic smoker for more than 10 years (10 cigarettes/day) but had stopped smoking upon diagnosis of laryngeal cancer.

Physical examination of the patient was unremarkable. High-resolution CT scan confirmed the presence of a peripheral lung nodule in his right lower lobe lateral-basal segment that was suspicious for malignancy. It measured 12 mm in diameter and had a spiculated border with a central cavity (Fig a). Another high-density 2-mm nodule was present in the right upper lobe subpleural region associated with apical fibrosis. There was pleural thickening and mildly increased peripheral lung markings in bilateral lower lobes. The peribronchiolar and hilar lymph nodes were not enlarged. After further examination and assessment of the surgical risk, video-assisted thoracoscopy was decided, with patient consent.

During video-assisted thoracoscopy, wedge excision of the nodule was done. Intra-operative frozen section consultation revealed a 10-mm papillary glandular tumour 8 mm away from the pleura. There was profuse mucin production and intra-alveolar extension suspicious for mucinous adenocarcinoma. Right lower lobectomy was subsequently performed, and the patient had an uneventful recovery. Microscopic examination of formalin-fixed paraffin-embedded sections from the nodule showed an arborising papillary tumour (Fig b) surrounded by intra-alveolar mucin. There was extension along the alveolar lining at its periphery (Fig b, inset) simulating ‘lepidic spread’ of adenocarcinoma. The papillary structures (Fig c and d) consisted of fibrous cores covered by single to multiple layers of mucin-secreting and ciliated (Fig d, inset) columnar cells and basal cells. There was focal tumour necrosis, rare mitoses, and mild nuclear atypia. Mucin and inflammatory cells filled the central cystic space. Origin from a dilated terminal bronchiole could be traced (Fig e). A batch of immunohistochemical studies showed CK7+/CK20- tumour cells mostly negative for thyroid transcription factor-1 except at the periphery, suggestive of residual alveolar lining cells. Monoclonal carcinoembryonic antigen highlighted the mucinous cells and p63 stained the basal cells. Proliferative index by Ki67 was low (5%). The overall picture was consistent with ciliated muconodular papillary tumour (CMNPT) of the lung. Examination of the lobectomy specimen showed focal peribronchiolar fibrosis compatible with the effect of smoking.1 These foci often contained peribronchiolar metaplasia featuring ciliated and mucinous columnar cells (Fig f) occasionally forming small papillae (Fig f, inset). The 2-mm lesion in the right upper lobe was a fibrotic nodule. The patient was well 1 year after surgery.

The term CMNPT of the lung was first used by Ishikawa in 2002 to describe a 1.5-cm peripheral lung nodule consisting of ciliated columnar cells, mucous cells and basal cells with papillary architecture. It was considered benign in view of indolent behaviour and bland-looking cells. Further reports by Ishikawa2 and others3 4 5 6 7 of similar tumours under various names (eg, solitary peripheral ciliated glandular papillomas, peripheral pulmonary papillary/glandular neoplasms with ciliated cells) supported this group of tumours as a specific entity that has not been included in the 2015 World Health Organization Classification of Lung Tumours.8 We searched the literature and reviewed 12 reports of 33 such tumours (online supplementary Appendix). Controversy exists whether CMNPT should be considered a benign tumour, a well-differentiated adenocarcinoma (in view of frequent intra-alveolar extension), or a spectrum of entities with possible progression. The consistent small size, slow growth rate, and lack of recurrence or metastasis after surgery support the benign nature of this tumour. Differentiation from mucinous adenocarcinoma is difficult for pathologists, especially during intra-operative frozen section, owing to the profuse mucin production and lepidic growth pattern. High-power examination revealing tripartite cell differentiation and lack of significant atypia in a clinically slow-growing lung nodule should raise suspicion of CMNPT. Wedge excision with clear margin is the treatment of choice. Our findings concur with a previous report3 of tumour origin from the terminal bronchiole. The finding of co-existing peribronchiolar metaplasia with similar cell components as CMNPT in the rest of the lung is unique. This suggests progression of disease from smoking-induced metaplasia to neoplasia during the pathogenesis. Although chronic smoking was noted in most male patients with CMNPT (14 out of 16 with smoking history specified in the online supplementary Appendix), co-existing peribronchiolar metaplasia was only briefly mentioned in one report,4 probably owing to limited sampling in wedge excision for most tumours. Molecular analysis for BRAF or EGFR mutations was not done in our case, because there was no therapeutic indication. Studies of CMNPT by Chuang et al5 and Lau et al6 yielded no KRAS or EGFR mutation. In contrast, Kamata et al7 reported mutations involving EGFR, BRAF, PTEN11, CTNNB1, IDH1, and TP53 in Asian patients and Liu et al4 reported mutations involving BRAF and AKT1 in one non-Asian patient. Because CMNPT is commonly reported in patients from East Asia, more reports are expected when awareness of this entity is raised among pathologists in this region. The pathogenesis, molecular characteristics, and natural behaviour of CMNPT can be better defined when more data are available.

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: FMF Cheung.
Acquisition of data: All authors.
Analysis or interpretation of data: All authors.
Drafting of the manuscript: FMF Cheung.
Critical revision for important intellectual content: All authors.

The authors would like to thank Dr Siu-wah Pang for contributing to the diagnosis of this tumour.

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 approved by the Ethics Committee of the University of Hong Kong–Shenzhen Hospital as original work with no infringement of personal privacy. The requirement for patient consent was waived by the Ethics Committee.

1. Katzenstein AL, Mukhopadhyay S, Zanardi C, Dexter E. Clinically occult interstitial fibrosis in smokers: classification and significance of a surprisingly common finding in lobectomy specimens. Hum Pathol 2010;41:316-25. Crossref

2. Ishikawa M, Sumitomo S, Imamura N, et al. Ciliated muconodular papillary tumor of the lung: report of five cases. J Surg Case Rep 2016;2016.pii:rjw144. Crossref

3. Aida S, Ohara I, Shimazaki H, et al. Solitary peripheral ciliated glandular papillomas of the lung: a report of 3 cases. Am J Surg Pathol 2008;32:1489-94. Crossref

4. Liu L, Aesif SW, Kipp BR, et al. Ciliated muconodular papillary tumors of the lung can occur in Western patients and show mutations in BRAF and AKT1. Am J Surg Pathol 2016;40:1631-6. Crossref

5. Chuang HW, Liao JB, Chang HC, Wang JS, Lin SL, Hsieh PP. Ciliated muconodular papillary tumor of the lung: a newly defined peripheral pulmonary tumor with conspicuous mucin pool mimicking colloid adenocarcinoma: a case report and review of literature. Pathol Int 2014;64:352-7. Crossref

6. Lau KW, Aubry MC, Tan GS, Lim CH, Takano AM. Ciliated muconodular papillary tumor: a solitary peripheral lung nodule in a teenage girl. Hum Pathol 2016;49:22-6. Crossref

7. Kamata T, Sunami K, Yoshida A, et al. Frequent BRAF or EGFR mutations in ciliated muconodular papillary tumors of the lung. J Thorac Oncol 2016;11:261-5. Crossref

8. Travis WD, Brambilla E, Burke AP, et al. WHO Classification of Tumours of the Lung, Pleura, Thymus and Heart. Lyon, France: International Agency for Research on Cancer; 2015.