What is the definition or description of: cavernous sinus tumor?

Various tumor types: The cavernous sinus is a venous sinus on both sides of the pituitary fossa, a complex area wherein the cranial nerves controlling eye movements, facial sensation/movement pass. The carotid artery also passes through this area. There are a variety of tumor types that can arise in this area ranging from benign/slow growing tumors-meningiomas /schwannomas to metastatic cancers. Treatment varies.

An important place: The cavernous sinus is a part of the system that drains blood from your brain. It drains blood from many of the deep veins. It is important because many vital structures run through it, including your carotid arteries and the nerves that control your eye movements and pupil reflexes. A tumor in this area can affect these vital structures.

Tumor: The cavernous sinus is a "lake" where many veins of the brain drain blood into. There are two such structures in the human brain (approximately behind each eye). These venous structures have walls and have nerves that run through them. When these lakes become involved with tumors, patient's can have dysfunction of these nerves (diploplia, facial sensation changes, and eye pain / visual loss).