LAUSR

DEAR EDITOR, A 47-year-old woman was diagnosed with primary cutaneous Rosai–Dorfman disease (a). The biopsy showed proliferation of histiocytoid cells with emperipolesis surrounded by polyclonal lymphocytes (b). S100 and other immunohistochemical studies confirmed the diagnosis (c). Surgical removal and methotrexate led to remission lasting 44 months. Twelve years earlier the woman had a primary cutaneous marginal zone B-cell lymphoma in the same cheek (d). Treatment with chemotherapy and local radiotherapy led to complete remission. A single case of the synchronic appearance of both diseases in the same patient has been reported to date. They may be different phenotypical expressions of the same process.