Multiple clear cell acanthomas. Case report and delineation of basement membrane zone antigens.

A case of multiple clear cell acanthomas is described with a review of the literature. This benign glycogen-rich epidermal tumor is generally unable to accept melanin and lacks phosphorylase or cytochrome oxidase activity. However, the basement membrane zone appears antigenically normal, as documented by the presence of epidermolysis bullosa acquisita antigen, bullous pemphigoid antigen, heparan sulfate proteoglycan, type IV collagen, and laminin by immunofluorescence microscopy.