Langerhans Cell Histiocytosis Involving the Skin of an Elderly Woman: A Satisfactory Remission with Oral Prednisolone Alone

Langerhans cell histiocytosis (LCH) is a disorder characterized by neoplastic proliferation of Langerhans cells that rarely involves the skin in adults. A 74‐year‐old woman presented with a fourteen year history of eosinophilic granuloma and bone involvement caused by LCH. She had received three combination therapy courses of curettage and radiation since 1987 and had remained free of LCH signs for seven years, after which she started to notice brown nodules on her left leg. Biopsy specimens taken from the lesions showed massive proliferations of large histiocytic cells. Immunoperoxidase stainings for CD1a and S‐100 protein were positive. Electron microscopy identified Birbeck granules in the cytoplasm of the atypical Langerhans cells. Treatment with oral prednisolone alone has resulted in the patient remaining in complete remission for 12 months.