Cutaneous T-cell-rich B-cell lymphoma in a horse.

The research provides details of a rare case of cutaneous T-cell-rich B-cell lymphoma in a 7-year-old horse. With a predominantly T-cell-rich lymphoma, the afflicted horse showed clinical signs like multiple cutaneous nodules, lymph node enlargement, rapid weight loss, and ventral oedema, followed by widespread body metastasis.

Case Description

• This case report discusses a variant of cutaneous malignant lymphoma typically seen in horses. The affected subject was a 7-year-old gelding.
• The signs observed included multiple cutaneous and subcutaneous nodules (tumor-like formations on the skin and beneath the skin), enlargement of superficial lymph nodes (immune system organs), dramatic weight loss, and ventral edema (swelling in the lower parts of the body).
• This particular type of cancer usually impacts female horses more regularly, but in this case, it was seen in a male horse.

Detailed Findings

• Upon his death, a necropsy of the horse revealed tumor infiltration into multiple lymph nodes throughout the animal’s body.
• There was also evidence of a single pleural mass (a tumor in the space surrounding the lungs), along with a few pulmonary and intestinal tumor nodules.
• All of these tumors were found to be densely populated with large lymphoblastic cells expressing CD79a (a marker of B-cells, a type of white blood cell) and numerous small, round, T lymphocytes expressing CD3 (a marker of T-cells, another form of white blood cell).

Diagnosis

• Based on these clinical observations and subsequent examinations, the diagnosis of cutaneous T-cell-rich B-cell lymphoma with metastases was confirmed.
• Rarity in horses, this case provides detailed insight into the disease’s clinical presentation and progression, which can be valuable for vet science in diagnosing and treating this form of lymphoma in horses in the future.