Muir–Torre syndrome (MTS) is a rare hereditary, autosomal dominant cancer syndrome that is thought to be a subtype of HNPCC (Hereditary Nonpolyposis Colorectal Cancer or Lynch Syndrome). Individuals are prone to develop cancers of the colon, breast, and genitourinary tract, and skin lesions, such as keratoacanthomas and sebaceous tumors (Sebaceous Adenomas). The genes affected are MLH1, MSH2, and more recently, MSH6, and are involved in DNA mismatch repair.