[The tip of the iceberg: multiple cutaneous sebaceous tumor in colon cancer. Muir-Torre syndrome--case report].

Muir-Torre syndrome is a rare genodermatosis with autosomal dominant inheritance. The syndrome is considered to be a subtype of the hereditary nonpolyposis colorectal cancer (or Lynch-syndrome). In two-third of the cases, it develops as the consequence of germline mutations in mismatch-repair genes--most commonly MutS Homolog-2 and MutL Homolog-1. Its diagnosis can be established if at least one sebaceous tumor (sebaceoma, sebaceous adenoma, epithelioma, carcinoma or basal-cell carcinoma with sebaceous differentiation) and/or keratoacanthoma and at least one internal neoplasm are present. Here the authors present the history of a 52-year-old man with multiple sebaceous carcinomas on his back. Immunohistochemical analysis showed the lack of MutL Homolog-1 protein expression in the tumor cells. Detailed clinical workup in order to identify internal malignancy found malignant coecum tumor. Histopathological evaluation of the sample from the right hemicolectomy revealed mid-grade adenocarcinoma with MutL Homolog-1 and postmeiotic segregation increased-2 deficiency. The detection of the cutaneous sebaceous carcinoma and the application of the modern diagnostic methods resulted in identification of the associated colorectal cancer in an early stage; hence, definitive treatment was available for the patient.