title: Extranodal Rosai-Dorfman disease: an uncommon cause of persistent nodule in the ear.
abstract: A 40-year-old woman presented with a nodule over the tragus of the right ear. A biopsy was initially reported as showing non-specific inflammation. In view of the persistence of the lesion, the histological material was reviewed, leading to revision of the diagnosis to Rosai-Dorfman disease, a diagnosis further confirmed by immunoreactivity of the histiocytes for S-100 protein. This case represented the extranodal form of Rosai-Dorfman disease in the absence of lymph node involvement.
authors.affiliation: Institute of Pathology, Queen Elizabeth Hospital, Kowloon, Hong Kong.
authors.forename: W Y
authors.initials: WY
authors.lastname: Tsang
authors.forename: J K
authors.initials: JK
authors.lastname: Chan
authors.forename: W K
authors.initials: WK
authors.lastname: Ho
authors.forename: H C
authors.initials: HC
authors.lastname: Yu
authors.forename: L T
authors.initials: LT
authors.lastname: Chow
mesh_terms: D000328:Adult; D004427:Ear Diseases / Q000473:pathology; D004431:Ear, External / Q000473:pathology*; D005260:Female; D006644:Histiocytes / Q000473:pathology; D015618:Histiocytosis, Sinus / Q000473:pathology*; D006801:Humans