[A case of benign cephalic histiocytosis]

A 15-month-old girl had an asymptomatic eruption of yellowish-brown flat papules of 12 months' duration. Those papules were seen multiply on her face and in a small number on her neck and trunk. Skin biopsy showed a massive infiltrate of histiocytic cells in the upper and middle dermis. Electron microscopically, these cells had comma-shaped bodies in the cytoplasm, and formed desmosome-like junctions at the cell peripheries. A diagnosis of benign cephalic histiocytosis was made on the basis of these clinical, histological, and ultrastructural findings. To the best of our knowledge, this is the first report of benign cephalic histiocytosis in Japan.