title: Probable essential thrombocythemia in a dog.
abstract: Essential thrombocythemia (ET) in an 11-year-old dog was characterized by persistently high platelet counts (range, 4.19 X 10(6)/microliters to 4.95 X 10(6)/microliters, abnormal platelet morphology, marked megakaryocytic hyperplasia in the bone marrow, absence of circulating megakaryoblasts, and history of splenomegaly and gastrointestinal bleeding. Increased numbers of megakaryocytes and megakaryoblasts (15% to 20%) in the bone marrow were confirmed by a positive acetylcholinesterase reaction. Another significant finding was the presence of a basophilia in blood (4,836/microliters) and bone marrow. The marked persistent thrombocytosis, absence of reactive (secondary) thrombocytosis, abnormal platelet morphology, and quantitative and qualitative changes in the megakaryocytic series in the bone marrow suggested the presence of a myeloproliferative disease. Cytochemical and ultrastructural findings aided in the diagnosis of ET. The dog was treated with radiophosphorus. The results was a rapid decline in the numbers of megakaryoblasts and megakaryocytes in the bone marrow and platelets and basophils in the peripheral blood. The dog died unexpectedly of acute necrotizing pancreatitis and diabetes mellitus before a complete remission was achieved.
authors.affiliation: Small Animal Internal Medicine Service, Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California, Davis.
authors.forename: P E
authors.initials: PE
authors.lastname: Hopper
authors.forename: C P
authors.initials: CP
authors.lastname: Mandell
authors.forename: J M
authors.initials: JM
authors.lastname: Turrel
authors.forename: N C
authors.initials: NC
authors.lastname: Jain
authors.forename: F
authors.initials: F
authors.lastname: Tablin
authors.forename: J G
authors.initials: JG
authors.lastname: Zinkl
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000473:pathology*; D001803:Blood Transfusion / Q000662:veterinary; D001853:Bone Marrow / Q000473:pathology*; D004283:Dog Diseases / Q000097:blood / Q000473:pathology / Q000532:radiotherapy; D004285:Dogs; D005260:Female; D006965:Hyperplasia / Q000662:veterinary; D008533:Megakaryocytes / Q000648:ultrastructure; D008854:Microscopy, Electron; D010761:Phosphorus Radioisotopes / Q000627:therapeutic use; D010976:Platelet Count; D013920:Thrombocythemia, Essential / Q000097:blood / Q000473:pathology / Q000532:radiotherapy / Q000662:veterinary*
chemical_list: D010761:Phosphorus Radioisotopes