Primary multiple colonic tumors of various genetic characteristics in a patient with familial adenomatous polyposis: description of the clinical case

Background. Familial adenomatous polyposis caused by abnormalities in the APC gene is detected in about 1% of patients with colorectal cancer. The prognostic significance of this mutation is extremely high, the risk of developing colorectal cancer in the first 40 years of life is 100%. Description of the clinical case. A rare case of the detection of primary multiple metastatic colon adenocarcinomas that developed as a result of familial adenomatous polyposis is presented. The tumor of the ascending colon was microsatellite stable, with the presence of the KRAS mutation. The tumor of the descending colon had rather rare genetic characteristics - a high level of microsatellite instability, HER2neu amplification, and the absence of RAS and BRAF mutations. Metastases also had different characteristics. An unusual torpid course of the disease in the absence of the pronounced clinical effects of drug therapy should be noted. The patient with initially metastatic colon cancer survived more than 5.5 years. Conclusion This observation justifies the alertness of the attending physicians regarding the possible development of multiple tumors with genetic heterogeneity of both primary and metastatic manifestations of colon cancer in patients with familial adenomatous polyposis.

familial adenomatous polyposis, colorectal cancer, immunogenetic study of tumors, chemotherapy