POLYCYTHEMIA-VERA IN A CAT - BONE-MARROW CULTURE IN ERYTHROPOIETIN-DEFICIENT MEDIUM

A 10-year-old, neutered male, domestic shorthair was referred with a h istory of progressive behavioral abnormalities and seizures. Clinical and laboratory evaluations revealed polycythemia (hematocrit 0.63 L/L) , neutrophilia (28.4xl0(9)/L, eosinophilia (6.37xl0(9)/L), and basophi lia (4.90xl0(9)/L) in the absence of dehydration. Feline leukemia and immunodeficiency virus tests were negative. Bone marrow aspiration and biopsy demonstrated panhypercellularity. Polycythemia vera (PV) was t he tentative diagnosis as arterial oxygen concentration was adequate, and neoplasia, cardiac dysfunction, and causes of renal hypoxia could not be detected. Erythropoietin (EPO) concentration by radioimmunoassa y (RIA) was 5.5 mU/ml. Erythroid colonies predominated when bone marro w was cultured in EPO-deficient medium. Treatment by phlebotomy over a period of three months resulted in remission of clinical signs; howev er, progressive recurrence of polycythemia at shortening time interval s prompted euthanasia. This case presented an unusual manifestation of myeloproliferative disease in cats with a diagnosis derived from a se ries of novel and specific tests.