Benign cephalic histiocytosis. A case report and ultrastructural study.

A 4-year-old Hispanic boy had an asymptomatic eruption of red-brown macules and papules on the face, neck, trunk, and upper extremities. Examination of the skin lesions by light microscopy revealed a diffuse infiltrate of histiocytes in the upper dermis. Examination by electron microscopy showed wormlike inclusion bodies within the histiocytes. A diagnosis of benign cephalic histiocytosis was made on the basis of these distinct clinical, histologic, and ultrastructural features.