Bone marrow necrosis in the dog.

Bone marrow necrosis in 4 dogs was characterized by refractory anemia with or without leukopenia and thrombocytopenia. Romanovsky-stained bone marrow had a diffuse blue discoloration, and marrow particles were elongated. Degenerating cells, cellular debris, and vacuolated macrophages also were seen. Examination of bone marrow sections revealed extensive replacement of normal stroma by necrotic debris and hemorrhage. The cause of the necrosis was not determined. Concomitant disorders included chronic ehrlichiosis, estrogen toxicosis, malignancy, endometrial cystic hyperplasia, and glomerulonephritis.