Subleukaemic T-Lymphoblastic Leukaemia in a Horse.
Abstract: A 20-year-old Dutch Warmblood gelding was referred with clinical signs of anorexia, weight loss, intermittent fever, cough, subcutaneous oedema and exercise intolerance. Haematological examination revealed the presence of blast cells, decreased lymphocytes, mild thrombocytopenia and anaemia but no leucocytosis. Serum analyses detected elevated aspartate aminotransferase and gamma-glutamyl transferase activities and triglyceride concentrations. Twenty-two days after the initial visit, the horse died after showing clinical signs of decreased appetite, increased body temperature, tachypnoea and tachycardia. At necropsy, there was mild splenomegaly but enlarged lymph nodes, masses or nodules were not seen in any organ. Histologically, neoplastic cells were seen in the subcapsular and medullary lymph sinus of the mediastinal, axillary, mesenteric and renal lymph nodes. The bone marrow was densely cellular with numerous large round neoplastic cells that had round nuclei with clear nucleoli and scant cytoplasm. The neoplastic cells were immunopositive for CD3 but negative for CD20, BLA36, CD204, Iba-1, CD204 and granzyme B. Based on these findings, the neoplasm was diagnosed as subleukaemic T-lymphoblastic leukaemia, which, to the best of our knowledge, is the first report of this neoplasm in horses.
Copyright © 2021 Elsevier Ltd. All rights reserved.
Publication Date: 2021-09-14 PubMed ID: 34686273DOI: 10.1016/j.jcpa.2021.08.002Google Scholar: Lookup
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Summary
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The study reports a unique case of a 20-year-old horse that was diagnosed with a rare type of leukemia, specifically subleukaemic T-lymphoblastic leukaemia. The horse presented symptoms including loss of appetite and weight, occasional fever, cough, fluid accumulation beneath the skin, and reduced endurance. Despite thorough evaluation, the cause of these symptoms was only found after its death.
Background
- The horse, a Dutch Warmblood gelding, displayed several clinical signs such as anorexia, weight loss, periodic fever, cough, fluid buildup under the skin, and diminished stamina during activity.
- A haematological evaluation was conducted on the horse which showed the presence of immature blood cells (blast cells), lowered levels of lymphocytes (a type of white blood cell), mild thrombocytopenia (low platelet count), and anaemia (low red blood cells).
- However, there was no leucocytosis which is an increase in the number of white cells in the blood, usually during infection.
Diagnosis and Results
- Further tests showed elevated levels of aspartate aminotransferase and gamma-glutamyl transferase activities (indicative of liver damage), and increased triglyceride concentrations (type of fat in blood).
- Unfortunately, 22 days after the initial visit, the horse passed away, exhibiting clinical signs like decreased appetite, increased body temperature, rapid breathing (tachypnoea), and fast heartbeat (tachycardia).
- A post-mortem examination revealed minor spenomegaly (enlarged spleen) but there was no notable enlargement of lymph nodes, or observable masses or nodules in any organs.
Post-Mortem Examination Findings
- However, microscopic examination of the tissues showed cancerous cells in certain areas of the lymph nodes including the mediastinal (chest region), axillary (armpit), mesenteric (abdominal), and renal (kidney).
- The bone marrow was densely packed with a large number of abnormally large round cancerous cells. These cells had round nuclei with clear nucleoli and very little cytoplasm.
- The cancerous cells tested positive for CD3 (an indicator of T cells – a type of white blood cell), but tested negative for CD20 (an indicator of B cells – another type of white blood cell), BLA36, CD204, Iba-1, CD204, and granzyme B.
Interpretation and Conclusion
- Based on these findings, the horse was diagnosed with a rare type of cancer known as subleukaemic T-lymphoblastic leukaemia.
- This particular type of leukaemia is rare and, to the best of the researchers’ knowledge, this is the first report of this cancer in horses.
Cite This Article
APA
Michishita M, Shibata R, Machida Y, Matsumoto M, Ochiai K, Azakami D.
(2021).
Subleukaemic T-Lymphoblastic Leukaemia in a Horse.
J Comp Pathol, 188, 21-25.
https://doi.org/10.1016/j.jcpa.2021.08.002 Publication
Researcher Affiliations
- Department of Veterinary Pathology, Nippon Veterinary and Life Science University, Tokyo, Japan; Research Center for Animal Life Science, Nippon Veterinary and Life Science University, Tokyo, Kanagawa, Japan. Electronic address: michishita@nvlu.ac.jp.
- Department of Veterinary Pathology, Nippon Veterinary and Life Science University, Tokyo, Japan.
- Department of Veterinary Pathology, Nippon Veterinary and Life Science University, Tokyo, Japan.
- PHIL Pet Clinic, Kanagawa, Japan.
- Research Center for Animal Life Science, Nippon Veterinary and Life Science University, Tokyo, Kanagawa, Japan; Department of Veterinary Hygiene, Nippon Veterinary and Life Science University, Japan.
- Laboratory of Veterinary Clinical Oncology, Tokyo University of Agriculture and Technology, Tokyo, Japan.
MeSH Terms
- Anemia / veterinary
- Animals
- Horse Diseases / diagnosis
- Horses
- Male
- Precursor Cell Lymphoblastic Leukemia-Lymphoma / diagnosis
- Precursor Cell Lymphoblastic Leukemia-Lymphoma / veterinary
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