title: Assessment of cytological criteria for diagnosing osteosarcoma in dogs.
abstract: OBJECTIVE
  To evaluate the specific cytological criteria of osteosarcomas in dogs.
  
  
  METHODS
  Significant cytological characteristics of osteosarcoma and benign mesenchymal bone proliferations were determined from imprint smears of 25 dogs with osteosarcoma (group 1) and 20 dogs admitted for removal of surgical bone implants after uncomplicated healing of bone fractures (group 2).
  
  
  RESULTS
  Mild to moderate cellular necrosis occurred frequently in patients with osteosarcoma. The cytoplasm of osteoblasts was pale blue to blue with a more pronounced basophilia in group 2. In 48 per cent of the patients in group 1, but none in group 2, osteoblasts showed a slight to moderate eosinophilic cytoplasmic granulation. In both groups, osteoblasts contained one red to pale blue nucleus with one or two grey-red to blue nucleoli in group 2. Forty-four per cent of animals in group 1 had osteoblasts with more than two nucleoli per nucleus. The median nuclear:cytoplasmic ratio was higher in group 1 (1:2.0) than in group 2 (1:3.5). Osteoblasts in group I were frequently seen to have a clumped chromatin pattern and showed significantly more criteria of malignancy (median six criteria per patient) than those in group 2 (median two criteria per patient). In group 1, mitoses of osteoblasts were detectable in 23 of 25 dogs, whereas only one dog in group 2 had evidence of mitotic osteoblasts.
  
  
  CONCLUSIONS
  Cytological criteria can be helpful in the diagnosis of canine osteosarcoma.
authors.affiliation: Small Animal Clinic, Department of Veterinary Medicine, Free University of Berlin, Oertzenweg 19b, 14163 Berlin, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Reinhardt
authors.forename: C
authors.initials: C
authors.lastname: Stockhaus
authors.forename: E
authors.initials: E
authors.lastname: Teske
authors.forename: R
authors.initials: R
authors.lastname: Rudolph
authors.forename: L
authors.initials: L
authors.lastname: Brunnberg
mesh_terms: D000818:Animals; D001859:Bone Neoplasms / Q000175:diagnosis / Q000662:veterinary*; D016022:Case-Control Studies; D003584:Cytological Techniques / Q000662:veterinary*; D004283:Dog Diseases / Q000175:diagnosis* / Q000473:pathology; D004285:Dogs; D012516:Osteosarcoma / Q000175:diagnosis / Q000662:veterinary*; D011237:Predictive Value of Tests