A clinical case of acute myelomonocytic leukemia in a Holstein cow

Abstract

A 2-year, 3-month-old Holstein cow presented with anorexia and enlarged superficial lymph nodes. Fine needle aspiration cytology of the superficial lymph nodes revealed large blast cells. Hematological examination revealed anemia, neutropenia, and blast cells in peripheral blood. Blast cells were the predominant cell type in bone marrow aspirates. Of the non-erythroid cells, 26%, 58%, and 18% were positive for myeloperoxidase, α-naphthyl acetate esterase, and naphthol AS-D chloroacetate esterase, respectively. Pathological examination revealed the proliferation of neoplastic cells, which were positive for monocytic markers, in the affected lymph nodes. The cow was diagnosed with acute myelomonocytic leukemia based on these findings. This report highlights the importance of performing bone marrow aspiration cytology and cytochemical staining when diagnosing bovine myeloid leukemia.

Acute myelomonocytic leukemia negative for alpha-naphthyl acetate esterase stain in a Holstein cow

“…Leukemia/lymphoma is a tumor of hematopoietic tissue that can be divided into two types based on the affected blood cell: myeloid leukemia and lymphoid leukemia [ 1 ]. Acute myelomonocytic leukemia (AMML) is a subgroup of myeloid leukemia and, to our knowledge, only two cases have been reported in cattle [ 6 , 12 ]. Monocytes are usually strongly positive for alpha-naphthyl acetate esterase (ANAE), and ANAE staining is commonly used to diagnose monocytic malignancy [ 1 , 6 , 12 ].…”

“…Acute myelomonocytic leukemia (AMML) is a subgroup of myeloid leukemia and, to our knowledge, only two cases have been reported in cattle [ 6 , 12 ]. Monocytes are usually strongly positive for alpha-naphthyl acetate esterase (ANAE), and ANAE staining is commonly used to diagnose monocytic malignancy [ 1 , 6 , 12 ]. In the present report, a case of ANAE-negative AMML in a Holstein cow was diagnosed by bone marrow aspiration and immunohistochemical staining using lymphocytic markers (CD3 and BLA-36) and monocytic markers (HLA-DR and Iba-1).…”

“…N/A, not applicable. ) [ 6 ]. However, blast cells were observed, constituting up to 24.2% of all nucleated cells (ANCs) and 44.8% of all non-erythroid cells (NECs) ( Fig.…”

“…Therefore, the cow was diagnosed with AMML, despite the ANAE-negative tumor cells. To the best of our knowledge, this is the third report of bovine AMML and provides additional information regarding the clinicopathological aspects of bovine AMML [ 6 , 12 ]. Incidence of AMML in cattle has never been investigated, and additional studies are needed to clarify the incidence of AMML in cattle.…”

“…Iba-1 is a marker for identifying neoplasms of monocytic origin with higher sensitivity and specificity than CD14, CD68, and CD163 [ 14 ]. In present case and previous bovine AMML case, Iba-1 was used as monocytic marker [ 6 ]. Therefore, although usefulness of those markers had not been evaluated in bovine monocytic leukemia, Iba-1 should be used as a monocytic marker in cattle with suspected monocytic leukemia.…”