Fortunately orbital tumors are very rare. There are over 1500 different tumors that can affect the orbit. The majority of these tumors are benign. These tumors cause problems because of their location and proximity to vital structures and organs including: the eye, the muscles that move the eye, the lacrimal gland, the nerves and vessels of the orbit, the sinuses and the brain. Occasionally, a malignant tumor may involve the orbit primarily or through spread from an adjacent or distant tumor. These lesions not only cause problems because of their proximity to vital structures, but also the risk of spread to adjacent and distant organs.