A case of bile duct carcinoma caused by lynch syndrome with subcutaneous mass

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, endometrial cancer, and so forth. Our patient was a 42-year-old Japanese woman with a right flank mass. We diagnosed undifferentiated hilar cholangiocarcinoma with multiple liver metastases (Stage IVb). At the age of 29, she had undergone surgery for sigmoid colon cancer. Six people among her second-degree relatives had colorectal or endometrial cancer, or brain tumors. She met the criteria of the revised Bethesda guidelines, and her microsatellite instability (MSI) test showed MSI-H. The gene analysis demonstrated a mutation of the intron domain of Exon6 in MLH-1. She died of DIC soon after diagnosis. Based on the obtained genetic code, we identified 3 mutation carriers in this family. Not only the patient but the whole family is the target of surveillance for related tumors of Lynch syndrome. Diagnosis is very important for this inherited disease.