Extraocular sebaceous carcinoma in Muirr Torre Syndrome with unfavorable prognosis

Abstract

Sebaceous carcinoma (SC) is a rare malignant tumor derived from the adnexal epithelium of sebaceous glands. It has been traditionally classiWed into two variants on the basis of its location, extraocular and ocular sebaceous carcinoma. Extraocular sebaceous carcinoma is rare (25% of reported cases [1, 2]) and occurs most commonly on the face and scalp, but they have been reported to occur almost anywhere on the body. It can exhibit such a diVerent variety of histologic patterns and clinical presentations, and the diagnosis is often delayed for months to years. These carcinomas are commonly associated with Muirr Torre Syndrome (MTS). The MTS consists of a rare autosomal dominant condition characterized by the association of cutaneous sebaceous neoplasms (sebaceous adenoma, sebaceous epithelioma, or sebaceous carcinoma, basal cell carcinoma with sebaceous diVerentiation, with or without keratoacanthomas) and the presence of at least one internal malignancy [3–8]. The biologic behavior of SC depends on the site, but particularly debated whether there is a diVerent aggressiveness of origin. Most of the literature reports that ocular tumors are highly malignant neoplasms with frequent locoregional and/or distant metastasis and intracanial extension [9–13]; extraocular sebaceous carcinoma on the other hand are considered as slow growing tumors of low malignant potential [9, 10, 14, 15]. In fact 15–30% of the patients aVected by ocular SC developed metastasis to the lymphnodes; widespread metastatic disease secondary to extraocular SC is very uncommon. Classically it has been considered that when metastases occur, only regional lymphnodes were involved [16, 17]. Many authors consider the presence of histologic and immunohistochemistry indices prognostically unfavorable (small diVerentiation, presence of vascular or lymphocytic invasion and presence of a pattern of pagetoid cells) [9, 18–20]. The discussion on the biologic aggressiveness of the neoplasia is still open. To support the opinion that the behavior of extraocular SC is not signiWcantly diVerent from those arising in the ocular region, this report describes a highly aggressive scalp SC in an MTS case.