No Increase in IgG4-positive Plasma Cells in Limbal Rosai–Dorfman Disease

PURPOSE: Extranodal Rosai-Dorfman disease is a rare benign condition recently reported to sometimes show features of IgG4-related disease. The purpose of this study was to describe the corneal-limbal manifestation of the entity and to investigate whether numerous IgG4-positive plasma cells are associated with the disease at this site. METHODS: This is an interventional retrospective small case series. RESULTS: Two patients presenting with painless limbal mass lesions underwent total excisional biopsy with anterior lamellar keratoplasty for diagnostic and therapeutic purposes. Histopathologic evaluation of the specimens revealed inflammatory lesions containing atypical S100-immunoreactive histiocytes diagnostic of Rosai-Dorfman disease, but not an increase in the IgG4-positive plasma cells. Point mutations (V600E) in the BRAF oncogene were absent. CONCLUSIONS: Rosai-Dorfmann disease should be considered in the differential diagnosis of limbal mass lesions. Involvement at this site was not associated with BRAF mutation or IgG4 abnormalities in the cases examined.