is an autosomal dominant skin condition of genetic origin, characterized by tumors of the sebaceous gland or keratoacanthoma that are associated with visceral malignant diseases (cancers of the internal organs). The cutaneous characteristics of Muir-Torre syndrome are sebaceous adenoma, sebaceous epithelioma, sebaceous carcinoma, or multiple keratoacanthomas, whereas visceral malignant diseases include colorectal, endometrial, urological, and upper gastrointestinal tumors. Men are affected twice as often as women. Muir-Torre syndrome is associated with hereditary non-polyposis colon cancer (HNPCC), an autosomal dominant cancer genetic syndrome. Sebaceous neoplasms associated with Muir-Torre syndrome exhibit microsatellite instability (MSI), as do other HNPCC-related cancers. Source: Genetic and Rare Diseases Information Center (GARD), supported by ORDR-NCATS and NHGRI.