Secondary myelofibrosis in three dogs.

Myelofibrosis was diagnosed in 3 dogs. In each dog, there was evidence of concurrent bone marrow necrosis, suggesting that the myelofibrosis was a secondary change. This suggestion was supported by a lack of dysplastic changes in hematopoietic cells. Bone marrow necrosis in 2 of the dogs may have been the result of widespread malignancy. Reversal of the myelofibrosis in 1 dog suggested that myelofibrosis is not always a terminal disorder.