title: Comparison of accuracy of 14-, 18- and 20-G needles in ex-vivo renal mass biopsy: a prospective, blinded study.
abstract: OBJECTIVE
  To prospectively determine the accuracy of 14-, 18- and 20-G core needle biopsies to render the appropriate histological diagnosis of solid, enhancing renal masses, using a controlled, ex-vivo biopsy technique.
  
  
  METHODS
  From March 2007 to September 2007, 31 patients undergoing partial or radical nephrectomy were randomly selected for biopsy. After extirpative surgery, three ex-vivo biopsies were taken from each lesion with 14-, 18- and 20-G biopsy needles. One experienced genitourinary pathologist, unaware of patient identifiers and final pathology results, determined the biopsy histology and tumour grade, based on standard haematoxylin and eosin (H&E) techniques and immunohistochemistry.
  
  
  RESULTS
  The final pathological evaluation classified 21 masses (68%) as clear cell renal cell carcinoma (RCC), three (10%) as papillary RCC, three (10%) as chromophobe RCC, three (10%) as oncocytoma and one (3%) as a benign lymphoid infiltrate. The biopsy histology correlated with the final pathology in 29/31 cases (94%) with the 14-G, 30/31 cases (97%) with the 18-G and 25/31 cases (81%) with the 20-G needles. In two cases chromophobe RCC was misdiagnosed with oncocytoma, and vice versa.
  
  
  CONCLUSIONS
  In this study a minimum of an 18-G biopsy needle was the most accurate in determining the histological diagnosis. Clear cell and papillary RCCs were accurately diagnosed on biopsy using an 18-G, whereas oncocytoma and chromophobe RCC were difficult to differentiate using standard H&E techniques and immunohistochemistry.
authors.affiliation: Department of Urology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA. albbred@hotmail.com
authors.forename: Alberto
authors.initials: A
authors.lastname: Breda
authors.forename: Eric G
authors.initials: EG
authors.lastname: Treat
authors.forename: Leah
authors.initials: L
authors.lastname: Haft-Candell
authors.forename: John T
authors.initials: JT
authors.lastname: Leppert
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Harper
authors.forename: Jonathan
authors.initials: J
authors.lastname: Said
authors.forename: Steven
authors.initials: S
authors.lastname: Raman
authors.forename: Robert B
authors.initials: RB
authors.lastname: Smith
authors.forename: Arie S
authors.initials: AS
authors.lastname: Belldegrun
authors.forename: Peter G
authors.initials: PG
authors.lastname: Schulam
mesh_terms: D018249:Adenoma, Oxyphilic / Q000473:pathology*; D000328:Adult; D000368:Aged; D001707:Biopsy, Needle / Q000295:instrumentation / Q000592:standards*; D002291:Carcinoma, Papillary / Q000473:pathology* / Q000601:surgery; D002292:Carcinoma, Renal Cell / Q000473:pathology* / Q000601:surgery; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007680:Kidney Neoplasms / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009339:Needles / Q000592:standards; D009392:Nephrectomy / Q000379:methods*; D055815:Young Adult