Acute B-lymphoid leukemia in a mare: a case report

An 8-year-old Friesen mare was admitted to the Equine Clinic, University of Veterinary and Pharmaceutical Sciences, Brno, Czech Republic with ventral edema and weight loss which had proceeded over the course of a few weeks. Clinical examination revealed poor body condition, depression, weakness, pale mucous membranes, enlarged mandibular lymph nodes and ventral edema. Thoracic percussion revealed fluid level reaching the shoulder on both sides. CBC revealed a severe disproportion of red and white cells. The horse was anemic and there was leucocytosis with the majority being blast cells (leucocyte concentration was 450.4 × 109/l) which included mitotic figures. The serum chemistry profile revealed hypoalbuminemia and increased alkaline phosphatase bone isoenzyme (BALP was 784.3 μkat/l). Based on the number of precursors in the peripheral blood acute leukemia was diagnosed. The peripheral blood was examined by flow cytometry and cytochemistry. The final diagnosis was determined as acute B cell lymphoid leukemia. The mare was treated with corticosteroids. On the second day of treatment the white blood cell count and alkaline phosphatase level decreased. The improvement continued until the fifth day, when the mare's status deteriorated and the horse was euthanized. Gross examination was carried out but no neoplastic mass was discovered. Final differentiation between primary and secondary lymphoid leukemia was not possible in this case.