Immunotherapy of periocular squamous cell carcinoma with metastasis in a pony.

The research article discusses a successful immunotherapy treatment for squamous cell carcinoma in the eyelid of a 5-year-old pony, which had spread to the lymph node. Previous treatments, including cryotherapy, had failed to resolve the issue.

Introduction to the Case

• The patient in this study was a 5-year-old Pony of America mare referred for evaluation due to inflamed upper and lower right eyelids.
• Diagnosis revealed the presence of squamous cell carcinoma (a type of skin cancer) in the eyelids and ulcerative keratitis (a serious eye infection) which was secondary to self-trauma.
• The initial attempt to treat the eyelid cancer with cryotherapy (a method where extreme cold is used to destroy abnormal tissues) failed.

Immunotherapy Treatment

• Bacillus of Calmette-Guerin (BCG) was adopted as a new treatment strategy. BCG is a vaccine primarily used against tuberculosis, and in this case, it was used as an immunotherapy.
• Over a course of 17 weeks, multiple injections of BCG were administered which resulted in the progressive shrinkage of the tumor mass.
• However, metastasis (the spread of cancer cells from the original site to another part of the body) to the ipsilateral submandibular lymph node was also observed.

Outcomes and Observations

• After six months, the ocular neoplastic lesions (abnormal mass of tissue as a result of abnormal growth or division of cells in the eye) were no longer visible, while the size of the lymph node also had greatly reduced.
• Moreover, signs of recurrence were not noted, even 18 months after the initial diagnosis of metastatic disease.
• The researchers concluded that this case shows squamous cell carcinoma of the equine eyelid, which usually carries a poor prognosis, can be treated successfully with immunotherapy.
• Given the outcome, the researchers suggest that immunotherapy should be considered as a potential alternative to traditional treatments such as cryosurgery, radiotherapy, hyperthermy, and CO2 laser ablation, especially for cases involving the eyelid.