Immunoreactivity for Sox10 in Basaloid Neoplasms of the Skin.

Basaloid tumors of the skin pose a diagnostic challenge to pathologists, because the differential diagnosis is broad, sometimes with subtle differentiating features. We evaluated SOX10 expression in 120 primary cutaneous tumors with epidermal, sweat glandular, neuroendocrine/neuroectodermal, follicular, and sebaceous lineages. Our findings were compared with those of previous studies that evaluated SOX10 in tumors of the skin. SOX10 staining was seen in the majority of sweat gland tumors with the exception of syringoma and microcystic adnexal carcinoma. There were no immunoreactive cases among epidermal, neuroendocrine/neuroectodermal, follicular, or sebaceous tumors. These findings are comparable to reported in previous studies, and show SOX10 can be a useful adjunct in the differential diagnosis of nodular basaloid skin tumors. That marker has less utility in the assessment of sclerosing basaloid cutaneous neoplasms, because such tumors are almost uniformly nonreactive for it.