title: Renal mass core biopsy: accuracy and impact on clinical management.
abstract: OBJECTIVE
  The objective of our study was to determine the accuracy of imaging-guided percutaneous renal mass biopsy and its impact on clinical management.
  
  
  METHODS
  With institutional review board approval, we retrospectively reviewed imaging-guided renal biopsies performed by radiologists at our institution between February 1999 and July 2005. Patient records, pathology reports, and imaging studies were reviewed. Concordance of biopsy diagnosis and follow-up data was assessed. Significant impact on clinical management was determined in collaboration with two experienced urologists and was defined as a change from no therapy to therapy, including surgery, tumor ablation, chemotherapy, or radiation.
  
  
  RESULTS
  Two hundred seventy-six renal biopsies were performed during the study period. Of these, 123 were random biopsies and fine-needle technique was used for one; these 124 were excluded. One hundred fifty-two renal mass biopsies were performed using coaxial 18-gauge core needle technique in 125 patients (55 women, 70 men; average age, 60 years; range, 28-90 years). There were two (1.3%) postprocedural hematomas (one [0.7%] requiring blood transfusion) and one (0.7%) delayed renal pseudoaneurysm attributed to biopsy. No tumor seeding was identified. In 85 biopsies (56%), malignant neoplasm was found, 61 biopsies (40%) yielded benign findings, and six (4%) were nondiagnostic. The sensitivity for malignancy was 97.7%; specificity, 100%; positive predictive value, 100%; and negative predictive value, 100%. At least 92 (60.5%) biopsy results significantly impacted clinical management.
  
  
  CONCLUSIONS
  Imaging-guided percutaneous core needle biopsy of renal masses is safe and highly accurate. Tissue diagnosis alters clinical decision making in a majority of the cases and may allow a number of unnecessary nephrectomies to be avoided.
authors.affiliation: Department of Radiology, UH B1D407, University of Michigan Hospitals, Ann Arbor, MI, USA. katematuren@yahoo.com
authors.forename: Katherine E
authors.initials: KE
authors.lastname: Maturen
authors.forename: Hanh V
authors.initials: HV
authors.lastname: Nghiem
authors.forename: Elaine M
authors.initials: EM
authors.lastname: Caoili
authors.forename: Ellen G
authors.initials: EG
authors.lastname: Higgins
authors.forename: J Stuart
authors.initials: JS
authors.lastname: Wolf
authors.forename: David P
authors.initials: DP
authors.lastname: Wood
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001707:Biopsy, Needle / Q000379:methods*; D005260:Female; D006801:Humans; D007668:Kidney / Q000000981:diagnostic imaging / Q000473:pathology*; D007680:Kidney Neoplasms / Q000175:diagnosis* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011859:Radiography; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D025321:Surgery, Computer-Assisted / Q000379:methods*; D014463:Ultrasonography