Abstract
Lynch syndrome is an inherited disease caused by a pathological germ-line mutation in one of the mismatch repair genes, and is characterized by the development of colorectal cancer and endometrial cancer, among others. We report herein two patients with small bowel cancer associated with Lynch syndrome.
Case 1. A 76-year-old man was admitted with small bowel obstruction. He had undergone total colectomy for duplex rectal cancer and triple colon cancer 15 years earlier. Small intestinal endoscopy revealed tumor filling the lumen in the jejunum. The tumor was diagnosed as well differentiated adenocarcinoma by histological examination. Partial resection of the jejunum with regional lymphadenectomy was therefore performed.
Case 2. A 69-year-old woman was admitted to receive surgery for transverse colon cancer in the vicinity of the anastomosis by colonoscopy. She had undergone surgery for ascending colon cancer 20 years earlier. We incidentally detected two tumor lesions in the jejunum and terminal ileum during surgery and also performed partial resection of the small intestine.
Both cases met the criteria of the revised Bethesda guidelines, and the microsatellite instability (MSI) test showed MSI-H, so we clinically diagnosed Lynch syndrome.
We report two cases along with a literature review, because small bowel cancer with Lynch syndrome is considered relatively rare.
