THE MUIR-TORRE-SYNDROME - A RARE VARIANT OF HEREDITARY NONPOLYPOSIS COLORECTAL-CANCER ASSOCIATED WITH HMSH2 MUTATION

The Muir-Torre syndrome is a rare autosomal dominant disorder characte rized by the association of visceral malignancies with typical skin le sions. This syndrome is now considered a subtype of the more common he reditary nonpolyposis colorectal cancer syndrome (HNPCC). This last co ndition has been ascribed to mutations in four mismatch repair genes, and similar mutations, mostly located at hMSH2 gene, are now being des cribed in some Muir-Torre patients. We describe the case of a 64-yr-ol d woman with no family history of colorectal cancer, who developed two visceral malignancies belonging to the usual spectrum of hereditary n onpolyposis colorectal cancer (colon and stomach), beginning at age 41 . She additionally developed several skin tumors, including multiple k eratoacanthomas, thus fulfilling Muir-Torre diagnostic criteria. Becau se of her cutaneous phenotype, she was screened for DNA mismatch repai r gene mutations by in vitro synthetized protein assay (IVSP) and a tr uncating mutation was identified at hMSH2. We further discuss the clin ical significance of the Muir-Torre phenotype, the association of this syndrome with hMSH2 mutations and the important implications of genet ic diagnosis for the patient and her offspring. (Am J Gastroenterol 19 98;93:1572-1574. (C) 1998 by Am. Coll. of Gastroenterology).