Eosinophilic myeloproliferative disorder in a horse
Morris, D.D.; Bloom, J.C.; Roby, K.A.; Woods, K.; Tablin, F.
Journal of the American Veterinary Medical Association 185(9): 993-996
1984
ISSN/ISBN: 0003-1488 PMID: 6511643 Document Number: 231246
An eosinophilic myeloproliferative disorder resulted in oedema and haemorrhagic diathesis in a 10-month-old Standardbred colt. Laboratory abnormalities included severe thrombocytopenia, anaemia, mild hypoproteinaemia, and pronounced eosinophilia. Circulating eosinophils were immature or atypical with variation in granule size, disproportionate nuclear to cytoplasmic maturation, and abnormal nuclear size and shape. Bone marrow aspirate had mainly atypical eosinophil precursors, few erythroid precursors, and no megakaryocytes. A blood transfusion and dexamethasone therapy resulted in some improvement; however, the horse was killed because of poor prognosis. PM examination showed gastrointestinal parasitism; histologically the spleen was infiltrated by atypical eosinophils and there were sites of eosinophilopoiesis. The disease was broadly similar to idiopathic hypereosinophilic syndrome in man, but typical cardiac and neurological involvement of hypereosinophilic syndrome was absent. Progressive myelophthesis and pronounced eosinophil atypia suggested malignancy.