• oncology;
  • pathology;
  • second opinion;
  • small animal;
  • surgical pathology


Second-opinion histopathology is a common practice in human medicine to avoid unnecessary procedures, costs and to optimize therapy. Histopathology review has been recommended in veterinary oncology as well. In this prospective evaluation of 52 tumours over a 1-year period, there was diagnostic agreement between first and second opinions in 52% of cases. Twenty-nine percent of cases had partial diagnostic disagreement, most often a change in grade, tumour subtype or margin status. Nineteen percent had complete diagnostic disagreement, including a change in cell of origin or a change from benign to malignant. Minor disagreements, which would not affect treatment or prognosis, were present in 21% of cases. Major disagreements, which would affect either treatment or prognosis, were present in 37% of cases. Costs of ideal staging and treatment recommendations were considerably different between first and second opinions.