WHAT IS THE ROLE OF PERCUTANEOUS NEEDLE CORE BIOPSY IN DIAGNOSIS OF RENAL MASSES?

Introduction: The aim of this clinical study is to define the accuracy and acceptability of ultrasonography guided percutaneous needle core biopsy in diagnosis of renal masses. Materials and Methods: The data of 30 consecutive patients to whom needle biopsies were done and were surgically treated for renal masses in our clinic between January 2001 and August 2005 were evaluated. In all patients, needle biopsies were done percutaneously with 18 gauge needle under ultrasonography guidance. The pathology results of biopsy and surgical specimens were compared. Results: The mean age was calculated as 57 years (range: 34-77). The mean size of renal masses according to computerized tomography findings was calculated as 65 mm (range, 25-140 mm). Renal biopsies were done to 16 left and 14 right kidney masses. After first set of biopsies, diagnosis could be made in 27 of 30 patients (90%). According to biopsy results, 23 patients were diagnosed as renal cellular carcinoma, 4 patients as oncocytoma, 1 patient as angiomyolipoma, 1 patient as leiomyoma and 1 patient was diagnosed as normal kidney tissue. After pathologic examination of surgical specimens, benign lesions were diagnosed in 4 patients and renal cellular carcinoma was diagnosed in 26 patients. The accuracy of biopsies for histopathologic and Fuhrman nuclear grade evaluation were 77% (23/30) and 52% (12/23), respectively. The sensitivity and specifity of needle biopsy were calculated as 84.6% (95% CI, 65.1-95.5), and 75% (95% CI, 20.3-95.9), respectively. Negative predictive value for needle biopsies was calculated as 43%. Conclusion: Percutaneous renal needle biopsy has low sensitivity and specifity in the diagnosis of renal masses. Patients with negative biopsy results should be viewed with caution.