A Case Report on Lymphatic Leukemia in a Dairy Cow

Abstract

A 2-year-old Holstein cow had been manifesting such clinical symptoms as suggestive of traumatic pericarditis. Hematological examination revealed a remarkable increase in leukocyte count (37, 000), and a differential leukocyte count consisting of 95.0% lymphocytes, 3.5% neutrophils, 1.0% monocytes, and 0.5% acidophils. With a bad prognosis, the cow was sacrificed.
Postmortem examination revealed tumors in the neck and breast, and marked gelatinous infiltration in the neck, dewlap, and the posterior portion of the breast. A tumor in the neck contained a necrotic focus of fist size. The diaphragmatic, mesenteric, and othe lymph nodes were distinctly enlarged. The heart was covered with voluminous fat masses containing tumors of chicken egg size. The epicardium was thickened. The pericardium contained dark brown fluid.
Histopathologically, the tumors in the neck, anterior portion of the breast, and pericardium were composed of essentially the same tumor tissue. The tumor cells closely resembled lymphocytes. Large numbers of tumor-like cells were present in blood vessels of the sites of tumefaction. Hyaline degeneration occurred in the walls of some of the blood vessels. Argyrophil fibers were generally thick and coarse, and connected with tumor cells generally in a loose manner.
From these results, the cow was diagnosed as a case of lymphatic leukemia. It was the characteristic of this case that the clinical signs manifested had been very close to those of traumatic pericarditis.