Renal collecting duct carcinoma. Report of a case with urinary cytologic findings.

A case of collecting duct carcinoma of the kidney is presented with histologic and cytologic findings. Cytologic examination of voided urine showed glandlike clusters of large cells with granular cytoplasm and prominent nucleoli, along with normal transitional cells. Macroscopically the kidney had a pelvic tumor mass that, on microscopic examination, was consistent with renal collecting duct carcinoma. Urinary cytology is useful as a diagnostic procedure even in cases of rare entities, such as collecting duct carcinoma.