Acute myelomonocytic leukemia is described in a 4-year-old female dog. During a two month period it presented anorexia, lethargy and progressive wasting. Laboratory results showed severe anemia and acute renal impairment. An ultrassonographic examination revealed a mesogastric mass. Once the dog did not respond to treatment it was euthanatiized. Macroscopically, deep pallor of mucous membranes, poor body condition and dehydration were detected. Some lymph nodes were swollen and tumoral nodules were observed in the liver, pancreas, regional lymph nodes, spleen and duodenum. The microscopic lesion consisted of neoplastic infiltration of the bone marrow, spleen, liver and lymph nodes. The cells were blastic myeloid cells with scant cytoplasm, round or segmented nucleus, prominent nucleolus and diffuse chromatin pattern. Immunohistochemical stains for NP57 were positive. The tumor was classified as acute myelomonocytic leukemia because of the morphology of the neoplastic cells and the predominance of blastic cells in the bone marrow.
dog; acute myelomonocytic leukemia; histopathology; immunohistochemistry
