Ocular and periocular hemangiosarcoma in six horses.

The research article discusses the characteristics and prognosis of ocular and periocular hemangiosarcoma (a form of cancer) in horses based on a study of six individual cases, emphasizing on complete surgical excisions as a potential effective approach for treatment.

Research Method

• The researchers conducted a retrospective review of medical records from 2007 to 2015, looking specifically for horses with a histological diagnosis of ocular or periocular hemangiosarcoma.
• Data collected for each horse included: age, sex, breed, duration of clinical signs, prior treatment received, tumor size and location, medical and surgical treatments including postoperative chemotherapy, follow-up time, and outcome.
• All the collected histopathologies were reviewed by a board-certified pathologist.

Research Findings

• There were no consistent patterns in terms of the breed, age, or sex of horses diagnosed with ocular or periocular hemangiosarcoma among the six cases studied.
• The locations of the tumors varied: three in the temporal limbus, two in the third eyelid, and one in the uvea. Except for the horse with uveal hemangiosarcoma, the rest had lightly pigmented periocular haircoats.
• Pathologically, the hemangiosarcomas in all six horses showed high cellularity, nuclear pleomorphism, and inflammation. These characteristics were confirmed using a measure called the mitotic index, which ranged from 0 to 8 mitoses per 10 consecutive 400x microscopic fields.
• Five out of the six tumors showed signs of solar elastosis, indicating ultraviolet light-induced damage to the sub-epithelial collagen, suggesting exposure to ultraviolet light may contribute to the disease’s development.

Treatment and Outcome

• All six cases underwent surgical excision. Four out of six horses did not experience a recurrence of the tumor following the surgery.
• Three cases also received ancillary treatment with topical mitomycin C, a chemotherapy agent, and none of them had a recurrence of the disease postoperatively.
• In two cases where the disease did recur after surgery, there was histologic evidence indicating that the excision was not fully completed.
• The investigators concluded that complete surgical excision could be an effective treatment for ocular and periocular hemangiosarcoma in horses.