Ocular Squamous Cell Carcinoma in a Working Horse in India

Introduction
Neoplastic adnexal disease represents one of the most frequently encountered and therapeutically challenging ophthalmic problems of horses1.

Case presentation
A six year old bay stallion with a mass on the medial canthus of the left eye was presented to the Brooke clinic in Kanpur, uttar pradesh. the owner reported that
the mass was increasing in size daily. the mass caused obstruction of normal vision, irritation of corneal surface and discomfort due to gravitational forces. Consequently, the stallion had become anorectic, leading to progressive weight loss and reduced body condition. the tumour was diagnosed as ocular Squamous Cell Carcinoma (SCC) based on clinical history, symptoms and location.

Management and outcome
The cricket ball sized (circumference 22 cm) mass was surgically excised under standing sedation with xylazine (1.1mg/kg) and butorphanol tartrate (0.02mg/kg). after three weeks, the mass recurred. following the same procedure, the mass was excised adjunct with ampicillin- Cloxacillin (10 mg/kg iV) and combined with immunotherapy, compris- ing 3 consecutive shots of BCG (Bacilli Calmette Guerin) vaccine injected (1 ml) locally in the remnant of the mass at intervals of one week. Dexamethasone (0.5 mg/kg iV) was injected at the time of administration of each BCG injection to minimise risk of anaphy- lactic shock. Eight (8) weeks following the second excision no regrowth was noted and all surgical wounds had healed.

Discussion
SCC can appear anywhere on the body but in equines they are most often located in non-pigmented skin near muco-cutaneous junctions such as seen on the eye lids, vulva, or penis. use of BCG-based immunotherapy in cases of equine sarcoid has been widely reported but few reports relating to succesful treatment of SCC have been identified.