Diagnosis and Management of Familial Adenomatous Polyposis in Adolescence: Case Report and Review of Literature

Abstract

Introduction: Familial Adenomatous Polyposis (FAP) is characterized by development of numerous polyps (typically more than 100) in the epithelium of colon. Extra colonic manifestations of the disease are also common and 58-90% of FAP patents develop polyps in stomach and duodenum. The disease is most commonly inherited as an autosomal dominant trait caused by a germ line mutation of a tumor suppressor gene called the adenomatous polyposis coli gene in chromosome 5q21 and has a reported incidence of 1 in 5000 to 1 in 17000 live birth annually. If left untreated, the predisposition of malignant transformation is significant and typically occurs in the third to fifth decade of life with 100% disease penetrance by 40 years of age. In the United States, FAP is responsible for approximately 1% of all the colon cancer reported each year. We present four cases of FAP. Methods: Medical records of four patients diagnosed with FAP (defined on colonoscopy findings) at BGA were reviewed. The collected data included demographics, disease presentation, investigation, treatment, hospital charts, endoscopy, and pathology. Results: The median age at presentation was 14 (SD±2) years. Three patients had a strong family history (75%) and one patients who underwent genetic testing was positive for APC mutation. One patient presented in early childhood with failure to thrive and the most common presenting complaint was rectal bleeding (3/4, 75%). After diagnosis, all four patients were referred for surgical intervention. One patient underwent total Procto-colectomy and two patients underwent total Colectomy with rectal preservation and recovered with no major complications. As of now, fourth patient has not had any surgical intervention. All four patients had extra-colonic manifestations with Gastric polyps being the most common (2/4), one patient had Pancreatitis (1/4) and one developed Medullary Thyroid Cancer (1/4). During the follow-up period, nine Flexible Sigmoidoscopy were performed. Both patient with rectal preservation developed polyps in the rectum and the number of polyps ranged from 5-50. Ten follow-up Esophageo-gastroscopies were performed. Two patients had Gastric and duodenal polyps and one developed a single polyp near the Ampulla of Vater. Conclusion: Methods and intervals of surveillance for gastric lesions in patents with FAP are decided by individual patient presentation and further studies appear to be needed to establish guidelines.Figure: Patient profile.Figure: Extra colonic manifestations of FAP.