title: A case of orbital Rosai-Dorfman disease with IgG4 positive plasma cells.
abstract: A case of a 9-year-old Black African male with right-sided proptosis is presented. The clinical interpretation was that of orbital rhabdomyosarcoma and an incisional biopsy was performed. This revealed the typical features of Rosai-Dorfman disease, featuring S100 positive non-Langerhans histiocytes with emperipolesis. There were also numerous plasma cells in the biopsy, in the more fibrotic areas. More than 40% of these plasma cells were positive for IgG4. This case represents the first case in the orbit to make the association of IgG4 plasma cell positivity with Rosai-Dorfman disease. Potential associations are discussed, and the relevance of this finding to ophthalmic pathology interpretation and differential diagnosis are highighted.
authors.affiliation: National Specialist Ophthalmic Pathology Service, Dept of Histopathology, Royal Hallamshire Hosiptal, Sheffield , England , United Kingdom , and.
authors.forename: Hardeep Singh
authors.initials: HS
authors.lastname: Mudhar
authors.forename: Roseline
authors.initials: R
authors.lastname: Duke
mesh_terms: D002648:Child; D003937:Diagnosis, Differential; D005094:Exophthalmos / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery*; D015618:Histiocytosis, Sinus / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery*; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis; D007150:Immunohistochemistry; D008297:Male; D010950:Plasma Cells / Q000473:pathology*
chemical_list: D007074:Immunoglobulin G