Combination of Core Biopsy and Fine-needle Aspiration Increases Diagnostic Rate for Small Solid Renal Tumors

Aim: Our aim was to evaluate the performance of combination of fine-needle aspiration (FNA) and core biopsy (CB) as a method for the diagnosis of small solid renal tumors. Patients and Methods: Ninety patients with a radiologically detected small solid renal tumor (≤4 cm) underwent a biopsy. Patient underwent FNA (FNA group, n=32) or CB (CB group, n=30) or combination of both FNA and CB (combination group, n=28). The diagnostic rate and accuracy of both techniques were assessed. Results: The diagnostic rate of the combination group (92.9%) was superior to that of the FNA group (62.5%) and CB group (76.7%) (p=0.006, and p=0.147, respectively). In the combination group, 11 CBs were diagnostic with 13 nondiagnostic FNAs, while 4 FNAs were diagnostic with 6 nondiagnostic CBs. For tumors ≤2 cm, the combination of FNA and CB significantly increased the diagnostic rate, compared with FNA alone (p=0.033) and CB alone (p=0.044). The accuracy for FNA, CB and the combination of FNA and CB was 88%, 100% and 100%, respectively. Conclusion: The combination of FNA and CB increased the diagnostic rate of renal biopsy for the small solid renal tumors. The incidence of small renal tumors is rapidly increasing. About 20-30% of small renal tumors are benign (1). New treatment options such as ablative therapy are increasingly used for small tumors. Imaging alone is unable to predict the nature of renal tumors. For these reasons, the contemporary role of tissue diagnosis of small renal masses has been recently established (2). Fine-needle aspiration (FNA) cytology and core biopsy (CB) are two widely used and accepted methods for obtaining tissue material for diagnosis. In many tumors, FNA is an established technique, usually using 20-25 gauge needles, and generally provides a sample for cytological examination. Traditionally, FNA is preferred in obtaining the tissue of deeply placed lesions, tumors adjacent to major vessels or in cases in which the needle is to be passed through the bowel wall (3). Cytological samples can be immediately stained and examined, thereby providing a rapid diagnosis. The experience with the CB technique has improved considerably since the late 1990s. The tissue is usually obtained by using larger 14-18 gauge needles. The major advantage of CB includes the preservation of tissue architecture, which may be important in the assessment of subtyping of some tumours.