A Rare Case of Serrated Polyposis Syndrome with the MSH6 and SMARCA4 variants.

Serrated polyposis syndrome (SPS) is the most common form of polyposis syndrome and has been shown to increase the risk of colorectal cancer (CRC). The genetic pathway of CRC in SPS is different from the classic adenomatous polyposis coli (APC) pathway, which accounts for 70-80% of cases of CRC. Most commonly, SPS mutations include BRAF and KRAS, with activation of the RAS-RAF-MAP kinase pathway involved in the pathogenesis of serrated lesions. We present a rare case of SPS in a 32-year-old woman with MSH6 and SMARCA4 variants, which have not previously been reported in the literature. LEARNING POINTS: Patients with serrated polyposis syndrome should receive frequent colon cancer screening.Patients and their relatives should undergo surveillance. © EFIM 2021.