Hematologic abnormalities and outcome of 16 cats with myelodysplastic syndromes

We investigated the hematologic abnormalities and prognoses in 16 cats with myelodysplastic syndromes (MDS). Nonregenerative anemia, thrombocytopenia, and neutropenia were observed in 15, 13, and 4, respectively, of the 16 ca ts with MDS. Morphologic abnormalities characteristic of MDS included megal oblastoid rubricytes (9 cats), hyposegmentation of neutrophils (7 cats). nu clear abnormality of rubricytes (10 cats) and neutrophils (13 cats), and mi cromegakaryocytes (10 cats). Disease in these 16 cats was subclassified int o refractory anemia (RA; 8 cats), RA with excess of blasts (RAEB; 5 cats), RAEB in transformation (RAEB in T, 1 cat), and chronic myelomonocytic leuke mia (CMMoL 2 cats), according to the human French-American-British (FAB) cl assification. In the cats in which the clinical outcome was known. 3 of 6 c ats with high blast cell count MDS, including RAEB, RAEB in T and CMMoL. de veloped acute myeloid leukemia, but only I of 8 cats with low blast cell co unt MDS (RA) developed acute myeloid leukemia. Based on the Dusseldorf scor ing system for the prognosis of human MDS, the survival times of the cats s howing high scores (greater than or equal to3 points) were significantly sh orter than those of the cats with low scores (<3 points). The FAB classific ation and Dusseldorf scoring system were considered to be useful for predic ting the prognosis of feline MDS. Furthermore, 15 of the 16 cats with MDS i n this study were infected with feline leukemia virus, indicating its possi ble etiologic role in the pathogenesis of feline MDS.