title: Accuracy of percutaneous core biopsy in management of small renal masses.
abstract: OBJECTIVE
  To determine the sufficiency and accuracy of percutaneous core needle renal biopsy in patients with small renal masses (SRMs).
  
  
  METHODS
  A retrospective chart review was performed on those patients who had undergone image-guided 18-gauge core renal biopsy of SRMs < or = 4 cm from February 1999 to October 2006. The information obtained included the initial biopsy technique, pathologic findings, and the clinical outcome.
  
  
  RESULTS
  A total of 110 renal biopsies were performed for masses < or = 4 cm. The average renal mass size biopsied was 2.7 cm, with a median of 4 cores taken. Of the 110 biopsies, 100 (90.9%) were sufficient for diagnosis and 10 (9.1%) were indeterminate or provided insufficient tissue. Of the 100 diagnostic biopsies, 65% were interpreted as malignant and 35% as benign. There were 8 complications (7.2%), with 2 postprocedural hematomas (1.8%). Thirty-four patients underwent surgical extirpation; the ultimate histopathologic accuracy of biopsy compared with the final surgical pathologic finding was 100% (34/34) in these patients.
  
  
  CONCLUSIONS
  Image-guided core needle biopsy is highly accurate in SRMs, and more than one third of these lesions will be benign. With a low complication rate, core biopsy provides a histopathologic diagnosis that aids in decision-making for the growing number of incidentally detected SRMs.
authors.affiliation: Department of Urology, University of Michigan Health System, Ann Arbor, Michigan 48109-0330, USA.
authors.forename: Rou
authors.initials: R
authors.lastname: Wang
authors.forename: J Stuart
authors.initials: JS
authors.lastname: Wolf
authors.forename: David P
authors.initials: DP
authors.lastname: Wood
authors.forename: Ellen J
authors.initials: EJ
authors.lastname: Higgins
authors.forename: Khaled S
authors.initials: KS
authors.lastname: Hafez
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001707:Biopsy, Needle / Q000379:methods; D005260:Female; D006801:Humans; D007668:Kidney / Q000473:pathology*; D007680:Kidney Neoplasms / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012189:Retrospective Studies