Blindness associated with nasal/paranasal lymphoma in a stallion.

A 29-year-old stallion presented with bilateral blindness following the chronic purulent nasal drainage. The mass occupied the right caudal nasal cavity and right paranasal sinuses including maxillary, palatine and sphenoidal sinuses, and the right-side turbinal and paranasal septal bones, and cribriform plate of ethmoid bone were destructively replaced by the mass growth. The right optic nerve was invaded and involved by the mass, and the left optic nerve and optic chiasm were compressed by the mass which was extended and invaded the skull base.