Abstract

Background: Familial Adenomatous Polyposis (FAP) is a rare but critical genetic disorder that significantly increases the risk of colorectal cancer. Characterized by the development of hundreds to thousands of adenomatous polyps throughout the gastrointestinal tract, FAP typically manifests in adolescence or early adulthood. It is an autosomal dominant condition caused by mutations in the Adenomatous Polyposis Coli (APC) gene located on chromosome 5q21-22. Approximately one-third of FAP cases arise from de novo mutations in individuals with no prior family history of the disease. Methods: This case report details a 37-year-old male presenting with abdominal pain and rectal bleeding. Diagnostic evaluation included colonoscopy, which revealed over 150 adenomatous polyps throughout the colon and an ulceroproliferative lesion in the splenic flexure. Histopathological analysis confirmed the presence of tubular adenoma and adenocarcinoma. The patient underwent a thorough assessment including genetic testing to confirm the diagnosis of FAP and to investigate potential genetic predisposition for family members. Results: The patient’s clinical presentation, combined with colonoscopic and histopathological findings, confirmed the diagnosis of FAP. Genetic testing identified a mutation in the APC gene, consistent with the diagnosis. The patient had an extensive polyp burden in the colon and a malignant lesion, underscoring the high cancer risk associated with untreated FAP. The case emphasizes the critical need for early diagnosis and intervention. Conclusion: Early diagnosis of FAP is essential to prevent progression to colorectal cancer. Regular surveillance, including colonoscopy and upper gastrointestinal endoscopy, plays a pivotal role in managing polyps and reducing cancer risk. Prophylactic surgical interventions, such as colectomy with or without ileorectostomy or restorative proctocolectomy, are crucial in managing FAP and preventing cancer development. This case demonstrates the importance of considering FAP in patients presenting with colorectal symptoms, regardless of family history, and underscores the need for ongoing vigilance in monitoring and managing this hereditary condition.

Keywords: Familial Adenomatous Polyposis, Colorectal Cancer, Adenomatous Polyps, APC Gene Mutation, Prophylactic Colectomy