Classification of Canine Malignant Lymphomas According to the World Health Organization Criteria

Abstract

A study was carried out to test the accuracy and consistency of veterinary pathologists, not specialists in hematopathology, in applying the World Health Organization (WHO) system of classification of canine lymphomas. This study represents an initiative of the ACVP Oncology Committee, and the classification has been endorsed by the World Small Animal Veterinary Association (WASVA). Tissue biopsies from cases of canine lymphoma were received from veterinary oncologists, and a study by pathologists given only signalment was carried out on 300 cases. Twenty pathologists reviewed these 300 cases with each required to choose a diagnosis from a list of 43 B and T cell lymphomas. Three of the 20 were hematopathologists who determined the consensus diagnosis for each case. The 17 who formed the test group were experienced but not specialists in hematopathology, and most were diplomates of the American or European Colleges of Veterinary Pathology. The overall accuracy of the 17 pathologists on the 300 cases was 83%. When the analysis was limited to the 6 most common diagnoses, containing 80% of all cases, accuracy rose to 87%. In a test of reproducibility enabled by reintroducing 5% of cases entered under a different identity, the overall agreement between the first and second diagnosis ranged from 40 to 87%. The statistical review included 43,000 data points for each of the 20 pathologists.

B‐cell lymphoblastic lymphoma of the nictitating membrane as the first presenting sign in a 2‐year‐old Springer Spaniel

“…Lymphoblastic lymphomas are the most aggressive lymphoma subtypes encountered commonly in veterinary practice 18. Likewise, the present case showed a very aggressive behavior.…”

Flow Cytometric Characterization and Clinical Outcome of CD4+ T‐Cell Lymphoma in Dogs: 67 Cases

“…and E.J.E.) and classified according to WHO criteria 11. At the time of review, the pathologists were blinded to the results of flow cytometry and clinical data.…”

A double blinded, placebo-controlled pilot study to examine reduction of CD34+/CD117+/CD133+ lymphoma progenitor cells and duration of remission induced by neoadjuvant valspodar in dogs with large B-cell lymphoma

“…This could be attributed to improved management of cancer patients over time, but it also could be due to recruitment of a relatively uniform population of dogs based on clinical and pathologic criteria 23 . The latter possibility highlights the benefits of study designs that narrow disease heterogeneity, particularly for canine lymphoma where each disease entity in this complex should be considered as an individual condition.…”

“…However, outcomes were recorded to evaluate trends that could be used to design future studies or could be included in meta-analysis. Criteria for inclusion were (1) clinical diagnosis of multicentric lymphoma (WHO stage I-V); (2) confirmed WHO classification of large B-cell lymphoma (DLBCL or MZL in transition) 23 ; (3) favorable performance status with an expected survival time of ≥ 30 days; (4) body weight more than 15 kg (to allow adequate blood sampling) and less than 40 kg (to ensure dosing feasibility); (5) platelet count ≥100,000/ml and packed cell volume ≥30%; and (6) informed pet owner consent in writing. Criteria for exclusion were (1) disease substage b; (2) any previous therapy for lymphoma, including corticosteroids; (3) lymphomas classified as other than DLBCL or MZL in transition; (4) dogs from herding breeds with high frequency of inactivating MDR-1 polymorphisms 24, 25 ; and (5) significant co-morbidities, such as renal or hepatic failure, congestive heart failure, or clinical coagulopathy.…”