Squamous cell carcinoma on the eyelid of Nigerian albino horse

Abstract

Squamous cell carcinoma is the most common neoplasia of the skin in horses. An adult albino stallion of Nigerian indigenous (Arewa) breed used for military ceremonial parade was presented with the chief complaints of growth on left side lower eyelid and unilateral epiphora. Tentatively diagnosis of eyelid squamous cell carcinoma was made and managed successfully. Restraint was achieved using chlorpromazine as tranquilizer and physical method with the animal on right lateral recumbency for the surgery. Lidocaine-adrenaline 2% was used for local anaesthesia. The growth was debulked only once and chemotherapeutically treated using vincristine 1 mg for local infiltration once and 2 mg intravenously twice at 3 weeks apart. Tissue sample was preserved in formaldehyde-10% and processed for histopathological examination. Haematological findings pre-treatment were neutropenia, 32% (52 to 70%) and hyperproteinemia, 10.2 g/d L (6.0 to 8.5g/dL) which became neutrophilic leucocytosis 16.1 x 109/L (5.6-12.1 x 109/L) post-treatment. Histopathological findings were focal areas of keratin pearls surrounded by a concentric aggregation of cornified squamous epithelial cells. Massive undifferentiated tumour cells and inflammatory cells at different stages of mitosis were also observed. It was concluded that surgical excision of lesion and vincristine therapy twice at 3 weeks apart only was effective to cure the eyelid squamous cell carcinoma in the horse. It was recommended that surgical excision of growths and vincristine therapy given by intravenous and local infiltration routes should be used in management of eyelid squamous cell carcinoma in albino horses.