Primary malignant lymphoma of the urinary bladder is a rare disease, and it accounts for only 0.2% of all the cases of extranodal lymphoma. The prognosis of primary bladder lymphoma has been favorable, with many patients being alive and well several years after treatment. We report here on a case of primary diffuse large B cell lymphoma of the urinary bladder in a 75-year-old man patient who presented with a one-month history of persistent dysuria. The abdominal CT revealed a mass at the posterior wall of the urinary bladder. The tissue obtained by transurethral cystoscopy showed an atypical lymphoid proliferation, which was consistent with diffuse large B cell lymphoma. The patient received systemic chemotherapy of rituximab and CHOP (cyclophosphamide, doxorubicin, vincristine and prednisolone) and he achieved a significant partial remission. (Korean J Hematol 2009;44:104-107.)

Keywords: Urinary bladder, Primary, Diffuse large B cell lymphoma