Accuracy and clinical role of fine needle percutaneous biopsy with computerized tomography guidance of small (less than 4.0 cm) renal masses

PURPOSE: We evaluated the accuracy and clinical role of fine needle percutaneous biopsy of solid renal masses 4.0 cm or smaller with helical computerized tomography (CT) guidance. MATERIALS AND METHODS: In 88 consecutive patients (mean age 61 years) 88 biopsies were performed. Median tumor size was 2.8 cm. Tumor biopsy was performed with an 18 gauge needle using helical CT guidance in an outpatient setting. At least 2 whole cores per tumor were obtained. RESULTS: Biopsy material was insufficient for analysis in 3 (3.4%) procedures. Median tumor size of failed biopsies was 3.0 cm. There were 5 (5.6%) biopsies which revealed fibrosis and were considered inconclusive. A benign lesion was found in 14 (15.9%) biopsies. In the 66 biopsies positive for malignancy there were 65 cases of renal cell carcinoma and 1 lymphoma. A total of 62 patients underwent surgery. Biopsy changed tumor management in 42 (47.8%) patients who avoided radical nephrectomy, 13 of whom had a lesion which did not require surgery, 1 with a lymphoma and 28 who were treated with partial nephrectomy. Biopsy accuracy for histopathological tumor type and Fuhrman nuclear grade was 92% and 69.8%, respectively. No substantial morbidity occurred. CONCLUSIONS: Fine needle biopsy of small renal masses could select benign lesions for which observation might be an alternative to surgery. The accuracy of fine needle biopsy in identifying histological tumor type was high. However, biopsy was less accurate in evaluating Furhman grade. Biopsy with helical CT guidance could be a key point in tailored management of small solid renal masses and provide important information to those patients harboring renal masses.