Introduction: Creation of an ileal conduit is associated with complications. A few cases have been reported on tumor development in an ileal conduit; diffuse large B-cell lymphoma originating from an ileal conduit is extremely rare.
Case Presentation: A 62-year-old Japanese man who had undergone radical cystectomy and ileal conduit diversion 6 years previously presented with a whitish bulge that had developed on the surface of the ileal conduit during follow-up visit.