Histopathological classification and immunophenotyping of spontaneous canine lymphoma in Bangkok metropolitan

The purpose of this study was to examine the immunophenotype of canine lymphomas according to the updated Kiel classification adapted for canine species and to relate the immunophenotype to the anatomical classification, clinical stage, and the malignancy. Forty formalin-fixed embedded tissue sections from dogs affected with lymphoma during 2002–2008 at the Department of Veterinary Pathology, Faculty of Veterinary Science, Chulalongkorn University were retrospectively studied. Results indicated that the prevalence of canine lymphoma occurred at the average age of 7.6 years old. Of the total 40 samples, 67.5 % (27/40) and 32.5 % (13/40) were found among pure breeds and mixed breeds, respectively. The tumors were classified by anatomical locations: multicentric (25/40, 62.5 %), mediastinal (2/40, 5.0 %), alimentary (2/40, 5.0 %), extranodal (7/40, 17.5 %), and cutaneous (4/40, 10.0 %). The clinical stages are divided as 7.5 % (3/40), 17.5 % (7/40), 17.5 % (7/40), 45.0 % (18/40), and 12.5 % (5/40) in stages I–V, respectively. Histopathology categorization of the lymphomas into low and high grade was accounted for 34 % (17/40) and 46 % (23/40) cases, in that order. Both immunophenotyping cases were 50 % (20/40) of T-cell (CD3 expression) and B-cell (IgM expression) lymphomas. T-cell phenotype showed higher malignancy than B-cell phenotype.