Primary telencephalic lymphoma in a horse

Abstract

A case of T small cell type lymphoma in the brain of a horse is described. A 20-year-old female Crioulo equine showed neurological signs characterized by ataxia, circling and partial loss of smell and sight. During necropsy, a whitish, firm, unencapsulated mass compressing the structures of the nervous tissue was observed, extending from the olfactory bulb to the internal capsule of the right telencephalon. Microscopic examination showed the proliferation of round cells with a small to moderate amount of eosinophilic cytoplasm. Nuclei were centrally located, irregularly round and occasionally cleaved and hyperchromatic. Immunohistochemistry for CD3 showed a moderate diffuse cytoplasmic staining. This is a rare primary central nervous system lymphoma in horses, with few reports in the veterinary literature. Nevertheless, it should be considered as a differential diagnosis in equines with neurological signs.

Keywords

• Lymphoma
• CD3
• Central nervous system
• Horse.