An Unsuspecting Case of Familial Adenomatous Polyposis (FAP)

Familial adenomatous polyposis (FAP) is an inherited and rare disease that typically manifests in the second decade of life. FAP presents as an asymptomatic disease state in its early stages, which affects the gastrointestinal (GI) tract, making it difficult to diagnose. The disease is characterized by numerous adenomatous polyps in the colon or rectum. Adenomatous polyposis coli (APC) gene mutation allows for the unchecked growth of polyps and provides the path for cancerous proliferation. In FAP, APC mutation inheritance has a moderate preponderance for paternal origin. A family history of FAP is an indicator to start early screening in patients, especially those with a paternal family history of the disease. We present a 21-year-old male patient who presented to the clinic with normal hemoglobin, heme-positive stools, and no family history of FAP or colon cancer. The initial assessment and plan was an endoscopy to look for upper and lower GI causes, but if negative, a further hematologic workup would be required. This case highlighted the need for thorough follow-up and workup of occult GI bleed. Clinical suspicion for FAP should be kept in mind, especially in young patients without a family history and unexplained heme-positive stool. Other findings that could suggest FAP include a personal or family history of extra-colonic manifestations such as fibromas, osteomas, or dentition abnormalities.