Association of a parasagittal meningioma, supplied by the middle meningeal artery of ophthalmic origin, with an aneurysm. Case report.

A 56-year-old female was admitted because of repeated focal fits, weakness, and sensory disturbance of the left foot and leg. Computed tomography (CT) scan showed a high density mass in the right frontoparietal parasagittal region, and perifocal edema. Right internal carotid angiography revealed an unusual middle meningeal artery, which originated from the ophthalmic artery and supplied the vascular tumor. A saccular aneurysm was noted at the internal carotid-posterior communicating artery junction. Right external carotid angiography showed no conventional middle meningeal artery. Plain skull roentgenogram and bone window CT scan verified the presence of the right meningoorbital foramen (Hyrtl's canal) and the absence of the right foramen spinosum. The tumor was almost totally removed. The histological diagnosis was meningioma. Six weeks later the aneurysm was clipped. The ophthalmic artery occasionally provides most or part of the blood supply of the middle meningeal artery through anastomosis between the recurrent meningeal branch of the ophthalmic artery and the orbital branch of the middle meningeal artery. Twenty-nine such cases are analysed and the clinical significance of this vascular channel is discussed.