Diagnostic yield of renal biopsy immediately prior to laparoscopic radiofrequency ablation: a multicenter study.

Introduction: Ablative therapy is increasing for the management of small renal masses. Laparoscopic as well as percutaneous cryotherapy and radiofrequency ablation (RFA) have been utilized. Herein we review our experience with renal biopsy immediately prior to laparoscopic RFA.

Methods And Materials: A prospectively collected database containing all patients who underwent laparoscopic RFA by three different surgeons at two different institutions was reviewed. Renal biopsies were performed in each patient during transperitoneal laparoscopy after mobilization of the kidney and prior to RFA. The biopsy needle was passed percutaneously via a sheath through the abdominal wall. Multiple core biopsies (3-5) were taken under visual and ultrasonic guidance. All were submitted for permanent pathologic sectioning.

Results: 138 patients underwent renal biopsy prior to RFA. Mean tumor size was 3.0 cm (range 1.0-6.9). The mean age was 72 years (range 39-90). There were 42 females and 96 males. Mean blood loss was 28 ml (0-400 ml). Only 5 patients lost more than 50 ml, and in each case the bleeding was associated with complicated renal mobilization and dissection prior to biopsy. Final pathology revealed renal cell carcinoma in 95, oncocytic neoplasm in 26, and angiomyolipoma in 9.8 patients were considered to have nondiagnostic biopsies. In this group, final pathology revealed benign cysts in 3, inconclusive specimens in 3, fibrosis in 1, and normal tissue in 1. Hence, a clear diagnosis was possible in 130 of 138 patients, which is 94.2%. RCC was diagnosed in 68.8% of the patients, and in 73.1% of the conclusive biopsies. Eight patients had perioperative complications, including low-grade fevers (2) perirenal/retroperitonal hematoma (2), pleural tear/pneumothorax (2), CHF exacerbation, and wound infection.

Conclusions: In our multicenter experience, renal biopsy of 138 renal lesions at the time of laparoscopic RFA had a diagnostic yield of 94.2%. RCC was diagnosed in 68.8% of the patients, and in 73.1% of the conclusive biopsies.