title: The diagnostic yield of immediate postcryoablation biopsies of small renal masses.
abstract: OBJECTIVE
  To evaluate the diagnostic feasibility and reproducibility of immediate postcryoablation biopsies of small renal masses.
  
  
  METHODS
  Between December 2006 and July 2007, 21 intraoperative pre- and postcryoablation (18-gauge core) biopsies of renal masses were obtained. Evaluation of the biopsies by the institutional uropathologist was followed by a blind assessment by two other uropathologists. Tumor subtype and Fuhrman grade were determined by the three pathologists, while biopsy timing (before or after cryoablation) was only assessed by the two blinded pathologists. The diagnostic yield of the pre- and postcryoablation biopsies and interobserver agreement were calculated.
  
  
  RESULTS
  The mean size of the 21 cryoablated tumors was 2.8 cm. No significant bleeding occurred after any biopsy. Of the precryoablation biopsies 75-81% was correctly labeled as precryo, and 48% of the postcryoablation biopsies as postcryo. The diagnostic yield of the three pathologists for precryo biopsies ranged between 67% and 71%, and for postcryo biopsies between 48% and 71% (not statistically different). When combining both types of biopsies, the overall diagnostic yield was 81% for all pathologists. The interobserver agreement was "almost perfect" (kappa = 0.902) for precryo biopsies and "substantial" (kappa = 0.514) for postcryo biopsies.
  
  
  CONCLUSIONS
  This study shows that it is feasible to obtain histopathological diagnoses from postcryoablation biopsies with a diagnostic yield and interobserver agreement similar to precryoablation biopsies.
authors.affiliation: Department of Urology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Patricia W
authors.initials: PW
authors.lastname: Beemster
authors.forename: Isabel
authors.initials: I
authors.lastname: Trias
authors.forename: Fiebo J W
authors.initials: FJ
authors.lastname: ten Kate
authors.forename: Ferran
authors.initials: F
authors.lastname: Algaba
authors.forename: Hessel
authors.initials: H
authors.lastname: Wijkstra
authors.forename: Jean J M C H
authors.initials: JJ
authors.lastname: de la Rosette
authors.forename: M Pilar Laguna
authors.initials: MP
authors.lastname: Pes
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D003452:Cryosurgery / Q000379:methods*; D005260:Female; D006801:Humans; D007668:Kidney / Q000473:pathology*; D007680:Kidney Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged