Cytologic features of recurrent lymphoma involving the urinary bladder.

Recurrent lymphoma of the bladder only occasionally presents with genitourinary symptoms, and there are very few cases in the literature reporting the cytologic findings of involvement of the urinary bladder by lymphoma. We report the findings from a case of diffuse large B-cell lymphoma with immunoblastic morphology that was identified in a bladder barbotage specimen of a 77-year-old man who presented with recurrent urinary tract infection and hematuria. We describe the cytomorphological features of lymphoma cells in the urine and discuss the differential diagnoses. Correlation of cytologic findings with immunohistochemical results is crucial in the diagnosis of lymphoma involving the urinary bladder.