Cutaneous manifestations of the Proteus syndrome.

The Proteus syndrome is a rare disorder in which the major manifestations are skeletal overgrowth, digital hypertrophy, exostoses of the skull, and hamartomatous tumors. Numerous skin lesions also occur. We treated six individuals, all of whom had the features unique to this syndrome of marked hypertrophy of the skin of the soles. The palms were similarly involved in two patients. Light microscopy of biopsy material from thickened areas of the soles showed elongation of the cytoplasm of the basal cells. Large epidermal nevi were present in three persons, as were linear macular lesions with areas of depigmentation and hyperpigmentation.