Sebaceous Carcinoma as a Presentation of Muir-Torre Syndrome.

Muir-Torre syndrome (MTS) is a rare, autosomal dominant condition that is within the spectrum of Lynch syndrome (hereditary nonpolyposis colorectal cancer (HNPCC)). Sebaceous adenomas are among the most specific manifestations of MTS. Other malignancies include tumors of the colon, rectum, and genitourinary systems, such as endometrial, ovarian, urothelial, and prostate cancer. Individuals at risk for MTS are identified using the Mayo score, which assesses risk based on family history of Lynch syndrome-associated cancers, personal history of these cancers, and age at diagnosis of a sebaceous adenoma or visceral malignancy. We present a case of a firm, red-yellow papule on the upper extremity, which was revealed by a biopsy to be a sebaceous adenocarcinoma. Immunohistochemistry was significant for the loss of MSH2 and MLH1.