Familial Adenomatous Polyposis

Abstract

Familial adenomatous polyposis is an inherited, autosomal-dominant syndrome that is caused by a germline mutation of the adenomatous polyposis gene (APC). The syndrome is characterized by the development of hundreds to thousands of adenomatous polyps in the colon and rectum with nearly all patients developing colorectal cancer if prophylactic surgery is not performed. Benign extracolonic manifestations are seen with this syndrome and include upper gastrointestinal polyps, desmoids, epidermoid cysts, osteomas, and congenital hypertrophy of the retinal pigment epithelium (CHRPE). Malignant extracolonic manifestations have also been associated with this syndrome. The most common sites of extracolonic cancers that develop in these patients are duodenal, thyroid, brain, and liver. Prophylactic surgery should be performed shortly after the diagnosis of polyposis. Surgical options include total proctocolectomy with end ileostomy, total colectomy with ileorectal anastomosis, or total proctocolectomy with ileopouch anal anastomosis. The literature is reviewed with regard to these different procedures. Genetic testing has evolved over the past decade to play a key role in identifying at-risk individuals and assisting in recommendations made to these patients and their families with regard to screening, surgical treatment, and surveillance.