The effect of cryoablation on the histologic interpretation of intraoperative biopsy of small clear cell renal carcinoma and renal oncocytoma.

BACKGROUND AND PURPOSE: We evaluated the effects of the first freeze-thaw cycle of cryoablation on Fuhrman grade, histology, and tumor architecture of small clear cell renal carcinomas and renal oncocytomas using an 18-gauge needle biopsy. PATIENTS AND METHODS: Between August 2006 and June 2007, 11 patients underwent cryoablation for 14 renal neoplasms. A laparoscopic approach was employed using third-generation argon/helium cryotechnology. Biopsies were taken prior to and following the first freeze-thaw cycle. Each biopsy sample was semiquantitively evaluated for cytoplasmic fraying, nuclear hyperchromasia, nuclear breakdown, and tissue discohesion as well as Fuhrman grade and interpretability by a single pathologist. RESULTS: Eighteen precryoablation and 15 post-first freeze biopsies were taken. A tissue diagnosis was rendered in 100% of 11 patients. Pathologic diagnosis following the first freeze-thaw cycle of cryotherapy, as compared with the pretreatment biopsy, was accurate in 10 (91%) cases. Neither of the two post-first freeze biopsies in the remaining patient rendered a diagnosis: one had an insufficient quantity of tissue and the second missed the tumor, abstracting benign renal tissue. There was no significant difference in cytoplasmic fraying (P = 0.30), nuclear hyperchromasia (P = 0.43), nuclear breakdown (P = 0.58), or tissue discohesion (P = 0.84) observed between biopsies taken before and after the first freeze-thaw cycle of cryoablation. In no case did we note a change in Fuhrman grade greater than 1. CONCLUSIONS: One cycle of cryoablation does not significantly alter the architecture or Fuhrman grade of biopsy tissue, thus allowing for another method to obtain sufficient histologic tissue when bleeding is minimal.

Duke Scholars

Author John Francis Madden Pathology

Author Thomas James Polascik Urology