The Incidental Diagnosis: Familial Adenomatous Polyposis Unmasked by CT in a Young Male Presenting with Chronic, Refractory Anemia
Shamas Rafique, Iqra Rafiq, Saad A. Janjuah
Researchers' Journal of Internal Medicine.
Background: Familial adenomatous polyposis (FAP) is an autosomal dominant disorder characterized by early-onset colorectal adenomatosis and a near-absolute risk of malignancy. Young patients often present with nonspecific symptoms like chronic anemia, leading to diagnostic delays. Case Presentation: We report a 32-year-old male with no significant family history who presented with a 12-month history of severe, symptomatic iron-deficiency anemia (Hb nadir 4.9 g/dL), temporarily responsive to intravenous iron. Associated symptoms included fatigue, hematochezia, weight loss, and palpable abdominal masses. A contrast-enhanced computed tomography (CT) scan, obtained during the evaluation of severe anemia, revealed highly suggestive findings of innumerable colonic polyps. Subsequent colonoscopy revealed the classic phenotype of extensive polyposis, and biopsy confirmed tubular adenomas with low-grade dysplasia. Genetic testing identified a pathogenic APC variant (c.4391_4394del). He underwent total prophylactic colectomy with ileal pouch-anal anastomosis (IPAA). Management and Outcome: Postoperatively, high-output diarrhea was managed with loperamide and cholestyramine. At 6-month follow-up, his anemia had completely resolved (Hb 14.8 g/dL). Conclusion: This case underscores CT's role in suggesting FAP in cases of refractory anemia, prompting definitive endoscopic and genetic diagnosis and life-saving surgical intervention. Unexplained iron-deficiency anemia in young adults warrants thorough investigation to identify underlying polyposis syndromes.