title: Bilateral oncocytoma and the value of needle biopsy.
abstract: BACKGROUND
  Renal oncocytoma represents a diagnostic challenge to urologists. We present three patients with bilateral renal oncocytomas.
  
  
  METHODS
  All three patients presented with bilateral renal masses and through surgical means, were diagnosed with oncocytoma. Renal biopsies were used to diagnose oncocytoma in the contralateral kidney.
  
  
  CONCLUSIONS
  Considering oncocytoma represents up to 16% of renal masses, there is overtreatment of benign disease due the difficulty in distinguishing between histologies on radiographs. Even when the diagnosis of oncocytoma is made, concurrent renal cell carcinoma can be found in a small subset of patients. The value of renal biopsy in these patients thus becomes increasingly important. The accuracy of needle biopsy has improved and is relatively safe. Accuracy in establishing a diagnosis is better than 70% in most series. Tissue acquisition remains a barrier to accurate diagnosis. Although not routine, patients with bilateral masses or impaired renal function may be candidates for renal biopsy.
  
  
  CONCLUSIONS
  Oncocytoma in the setting of bilateral renal masses presents a difficult clinical scenario. The clinician must exclude renal cell carcinoma from the differential diagnosis. Renal biopsy represents a safe and accurate method towards that end so that patients can be followed radiographically.
authors.affiliation: Department of Urology, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA.
authors.forename: Bert S
authors.initials: BS
authors.lastname: Ivey
authors.forename: Karthik
authors.initials: K
authors.lastname: Devarajan
authors.forename: Chandru P
authors.initials: CP
authors.lastname: Sundaram
mesh_terms: D018249:Adenoma, Oxyphilic / Q000000981:diagnostic imaging / Q000473:pathology*; D000368:Aged; D001707:Biopsy, Needle / Q000009:adverse effects / Q000379:methods*; D006801:Humans; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D008297:Male; D014057:Tomography, X-Ray Computed