Anaplastic oligodendroglioma in an adolescent with Lynch syndrome

Lynch syndrome (hereditary non-polyposis colorectal cancer; HNPCC) is an autosomal dominant cancer predisposition syndrome with high penetrance. It is caused by heterozygous germline mutations in one of the DNA mismatch repair (MMR) genes MLH1, MSH2, MSH6, and PMS2. Carriers are at high-risk for developing colorectal carcinomas, as well as various extracolonic malignancies. This case report describes a 15 year-old male with a confirmed germline mutation of MSH2 and early onset anaplastic oligodendroglioma. The patient's tumor showed loss of expression of MSH2 and MSH6 proteins with normal microsatellite stability. The immunohistochemical staining pattern provided strong evidence to support the inclusion of anaplastic oligodendroglioma as part of the spectrum of tumors found in Lynch syndrome.