title: Accuracy of on-bench biopsies in the evaluation of the histological subtype, grade, and necrosis of renal tumours.
abstract: OBJECTIVE
  Few data are available on the diagnostic accuracy of kidney tumour biopsy.
  
  
  METHODS
  We sought to evaluate morphological diagnostic accuracy--such as histotype, Fuhrman grading, and necrosis--on a series of renal biopsies and matched whole tumours.
  
  
  RESULTS
  Among 56 renal tumours, the benign instances consisted of six oncocytomas (10.7%), one angiomyolipoma (AML; 1.8%), and one metanephric adenoma (1.8%). Malignant tumours consisted of clear cell renal cell carcinoma (RCC) in 37 cases (66.1%), papillary RCC in six cases (10.7%), chromophobe RCC in three cases (5.4%), and unclassified RCC in one case (1.8%). Core biopsies were conclusive in 53 cases (94.6%), identifying six (10.7%) benign and 47 (83.9%) RCCs. The accuracy in identifying histological subtype was 92%, and the concordance between core biopsies and surgical specimens was nearly perfect (κ = 0.858; p < 0.001). With regard to nuclear grade, the concordance index was only moderate (κ = 0.253) and the concordance between core biopsies and surgical specimens was fair (κ = 0.20; p = 0.11), such as for necrosis.
  
  
  CONCLUSIONS
  We concluded that the accuracy in identifying histological subtype is high. Tumours with oncocytic features are the most problematic for diagnosis. Results for nuclear grades and coagulative tumour necrosis are less convincing.
authors.affiliation: Department of Oncological and Surgical Sciences, Urologic Unit, University of Padua, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Ficarra
authors.forename: Matteo
authors.initials: M
authors.lastname: Brunelli
authors.forename: Giacomo
authors.initials: G
authors.lastname: Novara
authors.forename: Carolina
authors.initials: C
authors.lastname: D'Elia
authors.forename: Diego
authors.initials: D
authors.lastname: Segala
authors.forename: Marina
authors.initials: M
authors.lastname: Gardiman
authors.forename: Walter
authors.initials: W
authors.lastname: Artibani
authors.forename: Guido
authors.initials: G
authors.lastname: Martignoni
mesh_terms: D018262:Adenocarcinoma, Clear Cell / Q000175:diagnosis* / Q000556:secondary / Q000601:surgery; D000236:Adenoma / Q000175:diagnosis* / Q000601:surgery; D018249:Adenoma, Oxyphilic / Q000175:diagnosis* / Q000601:surgery; D000368:Aged; D018207:Angiomyolipoma / Q000175:diagnosis* / Q000601:surgery; D001706:Biopsy; D002292:Carcinoma, Renal Cell / Q000175:diagnosis* / Q000556:secondary / Q000601:surgery; D002467:Cell Nucleus / Q000473:pathology; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000175:diagnosis* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009336:Necrosis; D011446:Prospective Studies; D015203:Reproducibility of Results