Tumours of the eye and adnexa.

Most types of epithelial tumour of the eyelids, conjunctiva, and cornea occur in all species; the most common type occurring in any species is bovine squamous cell carcinoma. Iridociliary epithelial tumours and malignant melanomas are the most important intraocular tumours. The histological features of the tumours are described under the following main headings: epithelial tumours of the eyelids, conjunctiva, and cornea; mesenchymal tumours (extraocular, optic nerve and nerve sheath, and uveal tract); neuroectodermal tumours; and melanogenic tumours of the eyelids and conjunctiva and of the uveal tract.