Supplementary Material for: Cytomegalovirus Isolated to a Colon Polyp in a Patient with Ulcerative Colitis on Ozanimod: A Case Report

Introduction: Cytomegalovirus (CMV) infection is a notable gastrointestinal infection affecting immunocompromised patients. In the gastrointestinal tract, CMV often presents with patchy or diffuse mucosal involvement and can cause fulminant colitis. However, polypoid CMV lesions are rare. We present a case of a 49-year-old man with ulcerative colitis (UC) in remission on ozanimod who developed CMV isolated to inflammatory colon polyps. Case presentation: A 49-year-old patient with UC in clinical remission on ozanimod underwent routine surveillance colonoscopy, which revealed multiple inflamed polyps with white caps. Biopsy results confirmed inflammatory polyps with positive CMV immunostaining, while adjacent tissues and plasma CMV PCR tests were negative. The patient successfully completed a three-week course of valganciclovir. Follow-up colonoscopy revealed additional inflammatory polyps, but no evidence of CMV. He remained in clinical remission and continued ozanimod therapy. Conclusion: The unusual nature of this presentation suggests a clinically silent CMV reactivation or, alternatively, a primary CMV infection in our patient, with an unclear natural history and optimal management. This report emphasizes the importance of considering CMV in UC patients with unusual endoscopic findings and the need for multidisciplinary collaboration to optimize care.