Familial adenomatous polyposis

This code identifies a hereditary disorder characterized by the development of numerous adenomatous polyps in the colon and rectum, significantly increasing the risk of colorectal cancer. It is an autosomal dominant condition resulting from a germline mutation in the APC gene.

Use this code for patients diagnosed with familial adenomatous polyposis (FAP), including attenuated FAP. Documentation should clearly state the diagnosis of FAP, often confirmed by genetic testing or a strong family history combined with characteristic endoscopic findings of hundreds to thousands of colorectal adenomas.

• Do not confuse with other types of polyposis syndromes (e.g., Peutz-Jeghers, Juvenile Polyposis Syndrome), which have distinct codes.
• Code any associated malignant neoplasms of the colon or rectum separately, sequencing the malignancy first if it is the primary reason for the encounter.
• Ensure documentation specifies "familial" or "adenomatous polyposis" to support this specific diagnosis.