Peer-reviewed veterinary case report
Chronic Myelomonocytic Leukemia with Central Nervous System Involvement in a Dog.
- Journal:
- Journal of the American Animal Hospital Association
- Year:
- 2025
- Authors:
- Tartari, Ilaria et al.
- Affiliation:
- From Veterinary Neurological Center "La Fenice · Italy
- Species:
- dog
Plain-English summary
An 8-year-old male mixed-breed dog was brought to the vet because he had been getting weaker over the past two months, with a noticeable decline in the last two days. During the exam, the vet found that the dog had trouble moving all four legs and showed signs of unsteadiness and reduced response in his right eye. Blood tests showed a high number of certain white blood cells, and imaging of the brain and neck revealed multiple unusual areas. Analysis of the fluid around the brain and spinal cord showed abnormal cells similar to those found in the blood, leading to a diagnosis of chronic myelomonocytic leukemia (a type of blood cancer). The dog was treated with medications that initially improved his symptoms, but after six weeks, he returned with worsening neurological issues and started having seizures, suggesting a possible progression to a more severe form of leukemia.
Abstract
An 8 yr old, male, mixed-breed dog was presented with a 2 mo history of progressive weakness, worsened in the last 2 days before examination. Neurological examination revealed ambulatory tetraparesis, ataxia, and proprioceptive deficits in all four limbs. Menace response was reduced in the right eye and discomfort was detected on neck manipulation.  Hematologic abnormalities included marked monocytosis. Magnetic resonance imaging of the brain and cervical spinal cord revealed multifocal lesions with heterogeneous contrast enhancement. Cerebrospinal fluid analysis showed atypical monocytoid cells with similar cells to those observed in peripheral blood and in bone marrow preparations. The dog was diagnosed with chronic myelomonocytic leukemia. Prednisolone and toceranib were administered with improvement of the neurological signs. After 6 wk, the dog presented for worsening of neurological signs and with the onset of epileptic seizures. The results of flow cytometry were compatible with the possible transformation to acute myeloid leukemia. Although rare, myeloid leukemia may be included in differential diagnosis of patients with central nervous system signs, especially in dogs with relevant hematological abnormalities. In this case, cerebrospinal fluid examination played a key role identifying atypical cells.
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Search related cases →Original publication: https://pubmed.ncbi.nlm.nih.gov/39761570/