The cutaneous manifestations of sinus histiocytosis with massive lymphadenopathy.

Ten patients with sinus histiocytosis with massive lymphadenopathy (SHML) also had cutaneous involvement. Seven of the ten were children. The skin lesions were solitary in three patients and multiple in seven. They were papular or nodular, up to 4 cm in diameter, and often had a xanthomatous appearance. Microscopically, they were constituted by a dermal infiltrate made up predominantly of histiocytes, plasma cells, and lymphocytes. Some of the histiocytes contained phagocytosed lymphocytes in their cytoplasm. The microscopic differential diagnosis includes dermatofibroma, xanthoma, Tangier disease, histiocytosis X, reticulohistiocytoma, juvenile xanthogranuloma, and leprosy.