gastrointestinal disorders
Familial Adenomatous Polyposis
Diagnosis of Familial Adenomatous Polyposis
Colonoscopy Genetic testing of patient and first-degree relatives Offspring screened for hepatoblastoma Diagnosis of familial adenomatous polyposis is made by finding>100 polyps on colonoscopy. Although the characteristic lesions of familial adenomatous polyposis can be recognized on sigmoidoscopy, colonoscopy is usually done to detect a more proximal cancer, which would require evaluation for metastases before treatment. Diagnosed patients should have genetic testing to identify the specific mutation, which should then be sought in first-degree relatives. If genetic testing is unavailable, relatives should be screened with annual sigmoidoscopy beginning at age 12, reducing frequency with each decade. If no polyps are evident by age 50, screening frequency is then the same as for average-risk patients. Children of parents with familial adenomatous polyposis may be screened for hepatoblastoma from birth to age 5 years with annual serum alpha-fetoprotein levels and possibly liver ultrasound. 