Two cases of clear cell acanthoma: an immunohistochemical study.

Two cases of clear cell acanthoma are reported. The expression of carcinoembryonic antigen (CEA), involucrin and keratin proteins in the tumors was investigated immunohistochemically. In 1981, Penneys et al. reported that this tumor was not of sweat gland origin because of the absence of CEA. This study confirmed this, further, the pattern of positive reaction of involucrin also indicated that this tumor is not of sweat duct origin.