Fine needle aspiration biopsy in urothelial carcinoma of the renal pelvis.

Ten of 73 kidney neoplasms (14%) collected from the files of the Hospital de Navarra over a five-year period were urothelial carcinomas of the renal pelvis (UCRP). In 54 of 73 kidney neoplasms fine needle aspiration biopsy (FNAB) was performed. In seven cases a cytologic diagnosis of urothelial carcinoma was made. The majority of patients presented with pain and hematuria of short duration. In three cases a renal mass was detected by roentgenography. A filling defect in the collector system, with no conclusive roentgenographic diagnosis, was observed in the remaining cases. Computed tomography-guided FNAB was performed in all cases. Voided urine was collected for microscopic study in six cases. The cytologic pattern of all cases was similar to that of bladder urothelial carcinoma. This feature was particularly frequent in well-differentiated papillary carcinomas. The differential diagnosis with other kidney lesions based on cytologic findings was established. FNAB is useful not only in the preoperative diagnosis of UCRP but also in follow-up.