Stem Cell Disorders Due to Abnormal Development and Maturation in Cats


PetMD Editorial

Updated Aug. 24, 2022

Myelodysplastic Syndromes in Cats


Myelodysplastic syndromes are a group of disorders affecting the cat's hematopoietic stem cells, which forms the red blood cells, white blood cells, and platelets. These disorders are characterized by the abnormal development and maturation of hematopoietic stem cells, and may be primary (congenital) or secondary (due to cancer, drugs exposure, and/or infections).


Myelodysplastic syndromes more common in cats than dogs.


Symptoms and Types

  • Weakness
  • Lethargy
  • Pale mucous membranes
  • Weight loss
  • Excessive bleeding
  • Recurrent infections
  • Enlargement of spleen and liver




Myelodysplastic syndromes is often associated with FeLV infections. Other risk factors include:


  • Infections
  • Bone marrow dysplasia
  • Idiopathic neutropenia
  • Drug toxicity (e.g., estrogen, cytotoxic anticancer agents, or trimethoprim and sulfa combination)




You will need to give a thorough history of your cats’s health, including the onset and nature of the symptoms, to your veterinarian. He or she will then conduct a complete physical examination, as well as a biochemistry profile, urinalysis, and complete blood count (CBC). Blood testing is especially important in making the diagnosis, as it may reveal abnormal reduction in the number of blood cells (cytopenia). In some cats, megaloblastic anemia is also seen. 


Other abnormal findings may include large, bizarre platelets and immature granulocytes (type of white blood cells) with abnormal shape and sizes. Your veterinarian will also take bone marrow sample to evaluate the red blood cell and white blood cells production process and identify abnormalities.



Treatment is usually non-specific unless the underlying cause is identified. Often, cats suffering from myelodysplastic syndromes are prone to severe complications, such as infections, and require intensive nursing care. In these cases, these animal will undergo antibiotic therapy until their white blood cell count normalizes. These cats are also more susceptible to severe anemia and hemorrhages and will require multiple blood transfusions.


Living and Management


Regular blood testing is required throughout treatment to evaluate the animal's progress. Unfortunately, the overall prognosis of these animals is not good, even after treatment. Maintaining the cat stable is, however, necessary to prevent further aggravation of symptoms.

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