Large granular lymphocyte leukemia/lymphoma in six cats

Area of Science:

• Veterinary Pathology
• Immunohistochemistry
• Canine and Feline Neoplasia

Background:

• Large granular lymphocyte (LGL) lymphoma is a rare neoplasm in cats.
• Characterizing feline LGL lymphoma is crucial for understanding its origin and behavior.

Observation:

• Six feline cases of LGL lymphoma were identified using light and electron microscopy.
• Tumor cells exhibited characteristic azurophilic granules, negative for peroxidase but positive for chloroacetate-esterase and acid phosphatase.
• Immunohistochemistry revealed CD3 antigen expression and lack of CD20 antigen, with CD57 positivity in three cases, suggesting cytotoxic T or natural killer cell origin.

Findings:

• Neoplastic lesions were localized to the gastrointestinal tract and jejunal lymph nodes in three cats.
• Widespread organ involvement, including lungs, myocardium, and spinal cord, occurred in the other three cats, with two also presenting leukemia.
• The study indicates feline LGL lymphoma is more prevalent than previously assumed.

Implications:

• Feline LGL lymphoma shares significant features with human LGL disorders, offering comparative insights.
• Further research into feline LGL lymphoma can improve diagnosis and treatment strategies.
• This study highlights the importance of immunohistochemistry in diagnosing feline lymphoid neoplasms.