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

Masaki Maezawa, Ai Nakamichi, Nao Akiyama, Michihito Tagawa, Ken-Ichi Watanabe, Yoshiyasu Kobayashi, Hisashi Inokuma

The Journal of veterinary medical science 2021 Oct 31

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A 4-year, 7-month-old Holstein cow presented with anorexia. Physical examination revealed masses in the interscapular region and vagina. Blast cells were detected in the masses and peripheral blood by fine needle aspiration cytology and hematological examination. By bone marrow aspiration, blast cells constituted up to 24.2% of all nucleated cells, and 22% and 2% of non-erythroid cells stained positive for myeloperoxidase and alpha-naphthyl acetate esterase (ANAE), respectively. Pathological examination revealed the mass lesions consisted of a proliferation of tumor cells, which were positive for monocytic markers (HLA-DR and Iba-1). The cow was diagnosed with acute myelomonocytic leukemia (AMML). Even when tumor cells are ANAE-negative, AMML cannot be completely ruled out and should be considered when diagnosing cattle with leukemia/lymphoma.

Citation

Masaki Maezawa, Ai Nakamichi, Nao Akiyama, Michihito Tagawa, Ken-Ichi Watanabe, Yoshiyasu Kobayashi, Hisashi Inokuma. Acute myelomonocytic leukemia negative for alpha-naphthyl acetate esterase stain in a Holstein cow. The Journal of veterinary medical science. 2021 Oct 31;83(11):1643-1647