Benign cephalic histiocytosis.

A 2-year-old boy was seen because of an extensive asymptomatic papular eruption on the face, neck, and shoulders of 18-months' duration. A skin biopsy specimen revealed cellular infiltrates composed predominantly of histiocytes. Electron microscopy of biopsy material disclosed "comma-shaped" inclusion bodies in the cell cytoplasm, consistent with the findings described in benign cephalic histiocytosis. To the best of our knowledge, this is the first report of this clinical entity in the American literature.