Meningiomas of Anterior Clinoid Process as a Cause of Unilateral Loss of Vision

MENINGIOMAS constitute approximately 15% of all intracranial tumors. They appear to arise from clusters of arachnoid cells and tend to occur in specific sites. Meningiomas, because of their pathologic appearance and their lack of invasive properties, are considered benign tumors. However, their slow and frequently silent growth permits them to attain considerable size before surgical intervention is required because of obvious neurologic disturbance. To prevent a recurrence of the tumor, its complete extirpation is desirable. The size of the tumor frequently precludes its complete removal. The mass frequently becomes attached to important blood vessels and parasellar structures, making its removal hazardous (Fig. 1). The relatively high incidence of postoperative complications and the relatively high mortality rate associated with the removal of meningiomas situated in certain portions of the brain offer a challenge to the clinician and the neurologic surgeon. If the tumor is situated at certain places within the cranial