Snapshot A 17-year-old boy is seen after his annual colonoscopy. His mother and his older brother both died of colorectal cancer. Since 12 years old, he has been screened annually for colorectal cancer. This year, several hundred polyps are seen in his colon. Based on his own readings and his physician’s recommendation, he decides to undergo prophylactic colectomy. Introduction Thousands of polyps in the intestinal tract from genetic mutation Genetics autosomal dominant (AD) inactivating mutation in APC gene (adenomatous polyposis coli) on chromosome 5 tumor suppressor gene 2-hit hypothesis remember, loss of APC is the beginning of the path to colorectal cancer Associated conditions Gardner syndrome AD subtype with colonic polyposis and bony and soft tissue tumors Turcot syndrome variants include autosomal recessive (AR) or AD with colonic polyposis and medulloblastoma or glioblastoma multiforme ↑ risk for colorectal cancer start screening with sigmoidoscopy at age 12 annually ↑ risk for other cancers hepatoblastoma thyroid cancer pancreatic cancer Presentation Symptoms thousands of polyps develop at a young age rectum is always involved rectal bleeding or bloody stool abdominal discomfort Physical exam rectal polyps may be palpable on rectal exam ocular findings congenital hypertrophy of retinal pigment epithelium predicts FAP with 42% sensitivity and 97% specificity Evaluation Based on endoscopy, family history, and genetic testing Complete blood count with iron deficiency anemia Endoscopy with biopsy > 100 colorectal adenomatous polyps Genetic testing APC mutation Differential Peutz-Jegher syndrome Lynch syndrome Treatment Prophylactic surgical colectomy Routine screening with colonoscopy and endoscopy Prognosis, Prevention, and Complications Prognosis almost normal prognosis with colonic screening and colectomy Complications inevitable progression to colorectal cancer if no surgery at risk for other malignancies duodenal cancer hepatoblastoma thyroid cancer pancreatic cancer