title: Comparison of 2- and 3-category histologic grading systems for predicting the presence of metastasis at the time of initial evaluation in dogs with cutaneous mast cell tumors: 386 cases (2009-2014).
abstract: OBJECTIVE
  To compare the Kiupel (2 categories) and Patnaik (3 categories) histologic grading systems for predicting the presence of metastasis at the time of initial examination in dogs with cutaneous mast cell tumors (MCTs).
  
  
  METHODS
  Retrospective case series.
  
  
  METHODS
  386 client-owned dogs with cutaneous MCTs.
  
  
  METHODS
  Medical records of dogs with newly diagnosed, histologically confirmed cutaneous MCTs that had undergone complete clinical staging were reviewed for clinical and histopathologic data.
  
  
  RESULTS
  All Patnaik grade 1 MCTs (n = 52) were classified as Kiupel low-grade MCTs, and all Patnaik grade 3 MCTs (43) were classified as Kiupel high-grade MCTs. Of the 291 Patnaik grade 2 MCTs, 243 (83.5%) were classified as Kiupel low-grade tumors, and 48 (16.5%) were classified as Kiupel high-grade MCTs. Dogs with Patnaik grade 3 MCTs were significantly more likely to have metastases at the time of initial examination than were dogs with grade 1 or 2 MCTs (OR, 5.46), and dogs with Kiupel high-grade MCTs were significantly more likely to have metastases than were dogs with Kiupel low-grade MCTs (OR, 2.54). However, 3 of 52 (5.8%) dogs with Patnaik grade 1 tumors, 48 of 291 (16.5%) dogs with Patnaik grade 2 tumors, and 44 of 295 (14.9%) dogs with Kiupel low-grade tumors had metastatic disease.
  
  
  CONCLUSIONS
  Findings indicated that in dogs with cutaneous MCTs, prognostication should not rely on histologic grade alone, regardless of grading system used, but should take into account results of clinical staging.
authors: Department of Veterinary Sciences and Public Health, Faculty of Veterinary Medicine, University of Milan, 20133 Milan, Italy.
authors: Damiano
authors: D
authors: Stefanello
authors: Paolo
authors: P
authors: Buracco
authors: Silvia
authors: S
authors: Sabattini
authors: Riccardo
authors: R
authors: Finotello
authors: Chiara
authors: C
authors: Giudice
authors: Valeria
authors: V
authors: Grieco
authors: Selina
authors: S
authors: Iussich
authors: Massimiliano
authors: M
authors: Tursi
authors: Timothy
authors: T
authors: Scase
authors: Stefano
authors: S
authors: Di Palma
authors: Giuliano
authors: G
authors: Bettini
authors: Roberta
authors: R
authors: Ferrari
authors: Marina
authors: M
authors: Martano
authors: Francesca
authors: F
authors: Gattino
authors: Mary
authors: M
authors: Marrington
authors: Monica
authors: M
authors: Mazzola
authors: Maria
authors: M
authors: Elisabetta Vasconi
authors: Maurizio
authors: M
authors: Annoni
authors: Laura
authors: L
authors: Marconato
mesh_terms: D000818:Animals; D004283:Dog Diseases / Q000145:classification*; D004285:Dogs; D005260:Female; D008297:Male; D034801:Mastocytoma / Q000473:pathology / Q000662:veterinary*; D060787:Neoplasm Grading / Q000379:methods / Q000662:veterinary*; D012189:Retrospective Studies; D012878:Skin Neoplasms / Q000473:pathology / Q000662:veterinary*