Sebaceous carcinoma.

Sebaceous carcinoma is a rare, aggressive, malignant tumor derived from the adnexal epithelium of sebaceous glands. It may arise in ocular or extraocular sites and exhibits such a variety of histologic growth patterns and diverse clinical presentations that the diagnosis is often delayed for months to years. We discuss incidence as well as clinical, histologic, diagnostic, prognostic, and management issues of this aggressive neoplasm.