Periocular Sebaceous Carcinoma With Apocrine Differentiation: A Case Report and Review of the Literature.

A 61-year-old man presented with a dome-shaped tumor in the right eyelid. Histology revealed a cutaneous neoplasm with lobular growth pattern. It was composed of large basaloid cells, cells with sebaceous differentiation, and glandular structures with apocrine features. The immunohistochemical study revealed diffuse expression of CK7, EMA, and androgen receptors in the neoplastic cells. Gross cystic disease fluid protein-15 highlighted the luminal cells, consistent with apocrine differentiation. These findings fit with a sebaceous carcinoma with focal glandular apocrine differentiation ("sebo-apocrine" carcinoma). Metastasis to regional lymph nodes were diagnosed 12 months after the surgical procedure. After 3 years of follow-up, the patient is alive, with evidence of persistent locoregional metastasis, but no evidence of distant metastasis. Most cutaneous adnexal tumors present only one cell type of differentiation, but hybrid/combined tumors can occur. Despite "sebo-apocrine" tumors are not unexpected, due to their common origin in the follicular-sebaceous apocrine unit, they are very rarely reported.