[CT-guided percutaneous fine needle biopsy of solid tumors of the kidney]

This study was designed to evaluate the reliability and the role of percutaneous needle biopsy in the diagnosis of renal masses.

85 biopsies were performed in 74 patients (mean age: 62 +/- 14 years). The median tumour diameter was 4.44 +/- 2.53 cm. Biopsies were performed with an 18G ASAP* needle with CT guidance. 2 to 4 cores were obtained per patients. All biopsies were performed as an outpatient procedure.

Biopsies were uninterpretable in 15 cases (17%) (13 with normal or no renal tissue and 2 necrotic samples). A benign lesion was detected in 8 cases (4 fibrous lesions, 4 infectious lesions). In 3 cases, biopsies were suspicious of cancer, which was confirmed on definitive histology. In 59 cases, biopsies were neoplastic: 6 benign tumours (4 oncocytomas, 1 angiomyolipoma, 1 cystadenoma), 42 renal cell carcinomas (RCC) (conventional: 32, chromophobe: 3, tubulopapillary: 7), 5 urothelial carcinomas, 3 metastases, 2 lymphomas and 1 sarcoma. The median Fürhman grade was 2. 30 RCC were operated. The correlation coefficient for the biopsy and pathology histological type was 0.90. The median pathological Fürhman grade was 2. The biopsy results modified therapeutic management in 38% of cases. There was no morbidity, post-biopsy medical management was never required.

Biopsy of renal masses is reliable for evaluation of the histological type. The introduction of the CT scope should increase the accuracy of biopsies. The morbidity is low compared to that of diagnostic surgery.