Primary diffuse large B-cell lymphoma of the ileal conduit created after radical cystectomy.

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. Mass biopsy was performed and the histological diagnosis was diffuse large B-cell lymphoma. Positron emission tomography showed no metastatic lesions. We attempted chemotherapy because the tumor cells tested positive for CD20; after six courses of a regimen involving rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone; diffuse large B-cell lymphoma of the ileal conduit resolved gradually. The patient is alive and remains free from the diagnosed diffuse large B-cell lymphoma.

Conclusion: We reported an extremely rare case of diffuse large B-cell lymphoma originating from the ileal conduit created after radical cystectomy.