Spontaneous Erythroid Leukemia in a 6-Wk-Old Male Crlj:B6C3F₁ Mouse

Abstract

This report describes spontaneous occurrence of erythroid leukemia in a 6 week-old male Crlj:B6C3F₁ mouse. Macroscopically, severe hepatosplenomegaly was noted, but no abnormalities were observed in other tissues including the thymus and lymph nodes. Hematological examinations of blood and bone marrow smear preparations revealed marked proliferation of erythroid cells at various stages of maturation, but neither obvious atypia nor neoplastic proliferation of granulocytic cells was observed. Microscopically, there was marked infiltration of neoplastic erythroid cells into the hepatic sinusoids, splenic red pulp, and bone marrow, but there was no infiltration into the thymus or lymph nodes. Corresponding to the hematological findings, no distinct proliferation of granulocytic cells was detected microscopically. Immunohistochemical examination revealed that these cells were positive for hemoglobin. The present case of mouse erythroid leukemia closely resembles "pure erythroid leukemia" in humans.