Sebaceous carcinoma arising from sebaceoma.

Sebaceous neoplasms are rare adnexal tumors that can present a challenge to clinicians. Only four cases of sebaceous carcinoma with sebaceoma have been reported in the literature. Herein, we describe the case of a sebaceous carcinoma originating from a sebaceoma in a solitary nodule of the posterior neck. Immunohistochemically, the tumor cells were strongly positive for epithelial membrane antigen and p53. It is possible that adnexal carcinomas may arise from malignant transformation of their benign counterparts as well as de novo. Malignant transformation was likely in this case because the lesion was composed of distinct benign and malignant components, and the benign component showed the typical histopathological features of sebaceoma. This case underscores the fact that partial and superficial biopsies sometimes may not provide the correct diagnosis. If a surgeon suspects malignancy based on a clinical examination, then it is mandatory to perform a deep biopsy.