Double small bowel cancers leading to the diagnosis of Lynch syndrome with germline MSH6 mutation in an elderly patient

A female patient in her 80s was referred to our hospital because of an ileal tumor identified by capsule endoscopy. FDG-PET suggested double intestinal tumors not only in the ileum but also in the jejunum. The patient has cancer past history including sigmoid colon, rectum, and endometrium, and also had cancer family history fulfilling the revised Amsterdam criteria. Double balloon enteroscopy disclosed two ulcerated tumors in the jejunum and the ileum. Biopsy was diagnosed as adenocarcinoma pathologically, and microsatellite instability-high (MSI-H) genetically. Surgical resection was performed, and the jejunal and the ileal tumors were tubular (T2N0M0) and mucinous adenocarcinoma (T4N0M0), respectively. Germline mutation analysis revealed a pathogenic splice-site mutation in MSH6 .