[A Case of Diagnosed Lynch Syndrome in a Patient with Ureteral Cancer].

Lynch syndrome (LS) is an autosomal dominant genetic disorder in which tumors are known to develop at an early age. Upper tract urothelial carcinoma is one of the tumors related to Lynch syndrome. A 49-year-old woman visited a urologic clinic due to left abdominal pain. She had a history of ovarian cancer. Her mother had a history of colorectal cancer and renal pelvic cancer, and her grandmother had had colorectal cancer. After detailed examination, she received laparoscopic left nephroureterectomy and she was pathologically diagnosed with left ureteral cancer. LS was suspected based on her past history, family history, and age. A microsatellite instability (MSI) test gave a positive result, and genetic analysis confirmed a mutation in the MSH2 gene, leading to the diagnosis of Lynch syndrome. Although LS has a high frequency of carcinogenesis, it is thought that an improved prognosis can be achieved by early discovery and treatment of cancer in LS patients. From our case report, we recommend screening of LS in patients with a past/family history, who have had an upper tract urothelial carcinoma. Once LS is diagnosed, the patient should be followed by a planned surveillance of cancer development.