[A Case of Lynch Syndrome with Muir-Torre Syndrome].

Muir-Torre syndrome(MTS)is a disease characterized by the simultaneous occurrence of sebaceous tumors and visceral malignant tumors. This syndrome is now considered to be a phenotypic variant of Lynch syndrome(LS). Our patient was a 58-year-old woman with a history of endometrioid adenocarcinoma of the uterine isthmus at the age of 40 years and left-sided triple negative breast cancer at the age of 44 years. At the age of 52 years, a multigene panel testing revealed a pathogenic variant in MSH2, and the patient was diagnosed with LS. During surveillance for LS in our department, a 2-mm sized intradermal nodule was found on the patient's left shoulder, at the age of 58 years. Histopathological examination of the resected intradermal nodule revealed a sebaceous adenoma. LS can present as MTS, and it is, therefore, important to conduct surveillance not only for visceral malignant tumors but also for skin tumors.