One hundred four cases of sebaceous carcinoma that arose from ocular adnexa, with at least five years' follow-up information following diagnosis, were studied to extend the authors' previous observations on various prognostic factors in these tumors. Twenty-three patients died from metastatic disease. Although sebaceous carcinomas elsewhere in the skin are rare, this study establishes that these neoplasms occur much more frequently in the ocular adnexa and have significant morphologic features that identify the more highly lethal carcinomas. The various clinicopathologic features that indicated a bad prognosis were vascular, lymphatic, and orbital invasion; involvement of both upper and lower eyelids; poor differentiation; multicentric origin; duration of symptoms greater than six months; tumor diameter exceeding 10 mm; a highly infiltrative pattern; and pagetoid invasion of the overlying epithelia of the eyelids. In many cases pagetoid change appeared to originate in the underlying sebaceous glands and from there extended to invade the overlying epithelia.