title: Percutaneous biopsy of renal masses: sensitivity and negative predictive value stratified by clinical setting and size of masses.
abstract: OBJECTIVE
  The purpose of our retrospective study was to evaluate the sensitivity and negative predictive value of percutaneous biopsy of renal masses stratified by clinical setting and the size of the mass.
  
  
  METHODS
  We categorized 115 consecutive percutaneous biopsies of renal masses in 113 patients into four clinical settings and three groups of mass sizes. The sensitivity and negative predictive value were computed (with 95% confidence intervals [CI]) for each clinical setting and for each size group.
  
  
  RESULTS
  For all procedures (n = 115), the sensitivity and negative predictive value were 90% (95% CI, 81-95%) and 64% (95% CI, 44-81%), respectively. For patients with a known malignancy who presented with a renal mass (n = 55), the sensitivity and negative predictive value were 90% (95% CI, 78-96%) and 38% (95% CI, 10-74%), respectively. For patients with no known malignancy and suspected unresectable tumor (n = 36), the sensitivity and negative predictive value were 92% (95% CI, 76-98%) and 0%, respectively. For patients with no known malignancy who presented with a cystic mass (n = 16), the sensitivity and negative predictive value were 33% (95% CI, 2-87%) and 87% (95% CI, 58-98%), respectively. For patients who were not surgical candidates with a renal cell carcinoma (n = 8) that was thought to be resectable, both the sensitivity and negative predictive value were 100%. For masses 3 cm and less (n = 31), the sensitivity and negative predictive value were 84% (95% CI, 63-95%) and 60% (95% CI, 27-86%), respectively. For masses between 4 and 6 cm (n = 42), the sensitivity and negative predictive value were 97% (95% CI, 83-100%) and 89% (95% CI, 51-99%), respectively. For masses greater than 6 cm (n = 42), the sensitivity and negative predictive value were 87% (95% CI, 71-95%) and 44% (95% CI, 15-77%), respectively.
  
  
  CONCLUSIONS
  Percutaneous renal mass biopsy has a high sensitivity in three clinical settings: patients with a known malignancy, patients with no known malignancy and suspected unresectable tumor, and nonsurgical patients with a mass suspected to be a resectable renal cell carcinoma. Negative results in small (< or = 3 cm) and large (> 6 cm) masses should be viewed with caution.
authors.affiliation: Department of Radiology, Brigham and Women's Hospital and Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA.
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Rybicki
authors.forename: Kirstin M
authors.initials: KM
authors.lastname: Shu
authors.forename: Edmund S
authors.initials: ES
authors.lastname: Cibas
authors.forename: Julia R
authors.initials: JR
authors.lastname: Fielding
authors.forename: Eric
authors.initials: E
authors.lastname: vanSonnenberg
authors.forename: Stuart G
authors.initials: SG
authors.lastname: Silverman
mesh_terms: D000368:Aged; D001707:Biopsy, Needle / Q000379:methods; D016001:Confidence Intervals; D005500:Follow-Up Studies; D006801:Humans; D007674:Kidney Diseases / Q000473:pathology*; D007680:Kidney Neoplasms / Q000473:pathology*; D008297:Male; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012680:Sensitivity and Specificity