A case of squamous cell carcinoma in an ewe

Squamous cell carcinoma is a tumour frequently found to occur in the reproductive tract of sheep.
This report describes the gross and histopathological characteristics of squamous cell carcinoma on
the head of an ewe. A sheep with a large mass of 9 X 15cm on the right lateral frontal region of the
head was submitted for post mortem. Necropsy examination revealed a firm, black lump with multiple
cavitations containing whitish pus. The neoplastic mass infiltrated and extended, completely covered
the right eye. Other adjacent structures appeared normal. Histopathological examination showed
typical neoplastic squamous epithelial cells arranged as islands and cords invading the basal
membrane and dermis from the epidermis. There were focal areas of necrosis, frequent and massive
keratinisation and pronounced infiltration of inflammatory cells predominantly mononuclear’s. This
paper reports a well differentiated malignancy of skin squamous epithelial/epidermal cells forming a
carcinomatous mass at a site of the head with abscess of skin not previously reported in ewe.