Needling renal cysts and tumours: cytology and radiology.

Renal masses found by intravenous urography, ultra-sound scanning, and arteriography were needled in 102 patients. Simple renal cysts containing clear fluid and no cytological abnormalities were found in 85 patients. Two unsuspected renal cell carcinomas were found on puncture; cytological examination showed malignant cells in the aspirate. Another five renal tumours were needled deliberately before nephrectomy, and a firm preoperative diagnosis of renal cell carcinoma was made on aspiration cytology in three. Benign cysts which had bled were particularly hard to diagnose. With care, radiology and cytology in combination can provide the firm diagnostic base needed for sound clinical management. The radiology-cytology team must be alert to the unusual finding that indicates a complex lesion, such as an unsuspected renal tumour.