Multiple primary cancer, including basal and squamous cell carcinomas of the skin with loss of mismatch-repair protein expression in a HNPCC family member – Case report

Background: Hereditary nonpolyposis colorectal cancer (HNPCC) is an inherited disease characterized by onset at an early age, an excess of synchronous and metachronous tumors and a variety of extracolorectal malignancies. Basal and squamous cell carcinomas of the skin are not customarily included in the tumor spectrum of HNPCC. HNPCC is caused by a germline mutation in one of the DNA mismatch repair (MMR) genes, most commonly MSH2 or MLH1, and typically presents with genomic instability and frequent loss of MMR protein expression in the tumor tissue. Patient: We report the case of a 62-year old woman who had a h…