Radiation-induced erythroleukemia in the beagle dog. A hematologic summary of five cases.

Eleven cases of myeloproliferative disease occurred in a group of 24 beagle dogs placed in a 60Co gamma-ray field at about 13 months of age and irradiated at an exposure rate of 5 R/22-hour day for duratior of life. Of these 11 dogs, 5 (described in this paper) were diagnosed as having erythroleukemia. The bone marrow showed marked erythroblastic hyperplasia, with maturation arrest of the erythroid elements, and increased numbers of myeloblasts and promyelocytes. The terminal peripheral blood was characterized by marked anemia and thrombocytopenia, with circulating erythrocytic precursors and abnormal erythrocyte morphology. Splenomegaly and hepatomegaly occurred in 4 of the 5 animals. In the spleens and livers of all 5, there was extensive leukemic infiltration and proliferation. The extent of leukemic involvement in other tissues and organs varied in individual dogs.