Neutrophilic Granulocytic Sarcoma and Acute Basophilic Leukemia in Cattle

Abstract

A case of neutrophilic granulocytic sarcoma and a case of acute basophilic leukemia are described. The former was diagnosed in an 8-year-old Holstein cow with a large intrathoracic tumor mass (case 1), and the latter in a 14-month-old Holstein heifer with a rapid increase in white blood cell count (case 2). In case 1, the tumor mass was composed of agranular cells and more mature cells with eosinophilic granules staining positive for naphthol AS-D chloroacetate esterase (CAE) and macrophage, myeloid/ histiocyte antigen (clone MAC387). In case 2, the tumor tissues consisted chiefly of myeloblastoid cells. However, differentiation to myelocytoid or metamyelocytoid cells was observed, and their intracytoplasmic eosinophilic granules were positive for tryptase (a marker for basophils and mast cells), but not for CAE (a marker for neutrophils and mast cells). Although reports of myeloid neoplasms are rare in cattle, as documented here, it is not difficult to diagnose them on the basis of histology, histochemistry and immunohistochemistry.

Erythroblastic sarcoma in the thoracic cavity of a cow

“…Reports of myeloid sarcoma are extremely rare in farm animals. Neutrophilic granulocytic sarcoma has been described in an 8-year-old cow [19] and a 3-year-old sow [12], and eosinophilic granulocytic sarcoma in a 5-year-old female pig [3]. Erythroid leukemia is also rare but has been reported in a calf [24] and a foal [7]; in the former, the number of nucleated cells was 30,800/ µl in the blood.…”

“…Hemoglobin, an excellent marker for erythroid differentiation in cattle [23], was demonstrated to be present in maturing tumor cells in the current case. On the other hand, not only B cell, T cell and other hematopoietic cell markers but also intracytoplasmic granules were absent [1, 8, 10, 13, 19, 22, 25]. This tumor was therefore judged to be a neoplasm of the erythroid lineage.…”

“…Although the thoracic bone marrow was affected by tumor, residual non-neoplastic hematopoietic and adipose tissues were extensive, and the tumor cells tended to form tumor masses or nodules and to be invasive into adjacent tissues rather than to proliferate in blood vessels. Only few tumor cells were hence observed in splenic red pulp, hepatic sinusoids and pulmonary capillaries, which are crowded with neoplastic cells in ordinary leukemias [16, 19]. On the basis of the clinical, macroscopic and histological results, a diagnosis of erythroblastic sarcoma was made [5].…”

“…This loss was clearly demonstrated by the finding that only half of the lymphatic tissue was infiltrated by neoplastic cells in the left superficial cervical lymph node. Likewise, in a case of neutrophilic granulocytic sarcoma of thoracic cavity origin in an 8-year-old cow, agranular tumor cells often did not resemble normal myeloblasts [19]. These sarcomas were not thought to terminate as acute leukemias, because of the poor condition or subsequent death of the cows.…”

“…Erythroblastic sarcoma occurs in infants with pure erythroid leukemia [14, 23], whereas de novo or primary erythroblastic sarcoma occurs in older persons [6, 18]. Acute myeloid leukemias including a case of pure erythroid leukemia usually occur in calves or young cattle [10, 17, 19, 21, 24], but myeloid sarcomas have been observed in adult or aged cattle and swine [3, 12, 19]. In cattle, myeloid sarcomas, characterized by the age predilection as well as no elevation of white blood cell count, formation of large tumor masses and unusual cytology of neoplastic cells [19], are quite different from common myeloid neoplasms (leukemias).…”