SOX10 immunohistochemistry in sweat ductal/glandular neoplasms.

Background SOX10 is a newer Schwannian and melanocytic marker that has generated great interest for its relative sensitivity and specificity in the diagnosis of neural crest-derived tumors. Previous studies with SOX10 have shown positive immunohistochemical expression in cutaneous eccrine glands and negative expression in eccrine ducts, apocrine glands and hair follicles. Thus, we hypothesized that some sweat gland tumors of presumed eccrine origin would be positive for SOX10, whereas apocrine-derived sweat gland tumors would not. MethodsA mouse monoclonal anti-SOX10 (clone BC34: Biocare Medical; Concord, California) immunohistochemical antibody was performed on various sweat gland tumors and basal cell carcinoma. Results SOX10 showed positivity in spiradenomas (13/13), cylindromas (9/10), hidradenoma papilliferum (10/10), syringocystadenoma papilliferum (8/10), apocrine adenomas (8/10), and negativity in poromas (0/12), syringomas (0/10), and basal cell carcinomas (0/13). There was mixed staining of hidradenomas (6/15). Conclusions SOX10 immunohistochemistry may be of utility in distinguishing some of the varying adnexal tumors from each other, and from basal cell carcinoma (BCC), but given the staining of both apocrine and eccrine tumors, does not seem to provide information as to their origins as either eccrine or apocrine tumors.