Hepatosplenic T-cell lymphoma in a mare.

This research shares the unusual case of a 21-year-old mare suffering from hepatosplenic T-cell lymphoma, a severe immune system condition affecting liver and spleen, which was identified through clinical evaluations, necropsy findings, and microscopic examinations.

The Case Presentation

• The research discusses a clinical case of a 21-year-old Dutch crossbred mare that was exhibiting symptoms of weight loss and weakness. This presentation of symptoms led to further investigation and clinical evaluation of the mare to understand the cause.

Clinical Findings

• Upon clinical evaluation, the mare was found to have severe anemia and thrombocytopenia (a condition characterized by a low count of platelets in the blood). This was accompanied by indications of hepatic disease (liver) and muscular damage.

Necropsy Findings

• Following the mare’s death, a necropsy (an autopsy for animals) was performed which revealed a rupture in the diaphragm and an extensive retroperitoneal hematoma (accumulation of blood in the space behind the abdominal cavity).
• The horse also showed signs of severe hepatosplenomegaly, which is simultaneous enlargement of both the liver (hepato) and the spleen (spleno).

Microscopic Analysis

• The researchers also conducted a microscopic analysis which revealed that the animal’s liver sinusoidal (small blood vessels inside the liver) and spleen’s red pulp (a soft inner part of the spleen) had abnormal infiltration of atypical CD3-positive lymphocytes. In healthy bodies, CD3-positive lymphocytes are components of the immune system that defend against invading pathogens.
• Importantly, no other nodal or extranodal sites in the mare’s body seemed to be affected by this cellular infiltration. This fact limited the disease to specific regions of the horse’ body.

Diagnosis

• Based on the clinical, necropsy, and microscopic results, it was determined that the horse had hepatosplenic lymphoma of probable T-cell origin. Lymphoma is a type of cancer that starts in the cells that are part of the body’s immune system. The specific hepatosplenic type of T-cell lymphoma is rare and characterized by cancer development in the liver and spleen.