The Utility of Using Immunohistochemistry in the Differentiation of Metastatic, Cutaneous Clear Cell Renal Cell Carcinoma and Clear Cell Hidradenoma

Abstract

Background

Clear cell hidradenoma and cutaneous clear cell renal cell carcinoma (CCRCC) overlap morphologically. The distinction may be difficult in a patient with a history of CCRCC, presenting with a cutaneous nodule, potentially leading to an erroneous diagnosis. We investigated the usefulness of napsin A and paired box gene 8 (PAX-8) with previously studied markers epithelial membrane antigen (EMA), carcinoembryonic antigen (CEA), vimentin and CD 10 in differentiating CCRCC from hidradenoma.

Methods

We evaluated hidradenomas and cutaneous CCRCCs for immunohistochemical expression of napsin A, PAX-8, EMA, CEA, vimentin, and CD10.

Results

PAX-8 was expressed in all CCRCCs (8/8) while negative in hidradenomas. Napsin A was negative in both hidradenomas (0/12) and CCRCCs (0/10). EMA showed membranous reactivity in 11/12 hidradenomas and 8/10 CCRCCs; and highlighted ductal epithelium in 1/12 hidradenomas and cystic areas in 4/10 CCRCCs. CD10 showed ductal expression in 3/12 hidradenomas and membranous staining in 8/9 CCRCCs. CEA highlighted ductal epithelium in 11/12 hidradenomas while absent in CCRCCs (0/10). Vimentin highlighted neoplastic cells in 8/8 CCRCCs and failed to stain the hidradenomas (0/12).

Conclusion

A conservative immunohistochemical panel including PAX-8, vimentin, and CEA allow for easy distinction of CCRCC from hidradenoma, whereas napsin A added no additional value.

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