Cronkhite-Canada syndrome after corticosteroid and mesalazine treatment: A case report and 3-year follow-up.

RATIONALE: Cronkhite-Canada syndrome (CCS) is a rare, nonhereditary gastrointestinal polyposis syndrome with known malignant potential. This case report aims to present the clinical course, management, and long-term (3-year) follow-up of a CCS patient, highlighting the discrepancy between symptomatic improvement and endoscopic progression, and to discuss associated carcinogenic risk. PATIENT CONCERNS: A 50-year-old man presented with diffuse abdominal pain of unclear origin, bloody stools, hair loss, melanosis on the hands, and nail dystrophy. DIAGNOSES: Laboratory tests revealed hypoalbuminemia, hypocalcemia, hypokalemia, and positive fecal occult blood. Enteroscopy and subsequent pathological examination confirmed the presence of characteristic intestinal polyps, leading to a diagnosis of CCS. INTERVENTIONS: The patient was treated with a continuous regimen of corticosteroids combined with mesalazine. After 1 year of medical therapy, he underwent endoscopic mucosal resection. OUTCOMES: The patient's clinical symptoms improved significantly following treatment. However, endoscopic and pathological findings showed a tendency to deteriorate over time. At the 3-year follow-up, this disparity between clinical well-being and pathological progression persisted. LESSONS: CCS carries a risk of malignant transformation. Even with clinical improvement on long-term corticosteroid and mesalazine therapy, endoscopic progression may occur. Therefore, we recommend intensive endoscopic surveillance every 3 to 6 months following initial diagnosis, maintained for at least the 1st year, as a strategy to mitigate cancer risk.