[Surgical excision of a huge olfactory groove meningioma by extensive transfrontal approach].

A case with a huge olfactory groove meningioma was cured surgically by extensive transfrontal approach. A 46-year-old female was admitted with complains of left visual disturbance. CT revealed a large high-density mass in the base of the frontal fossa which was enhanced homogenously. Hyperostosis was seen in the planum sphenoidale. MRI showed a relatively low intensity with a peritumoral low-intensity rim on T1WI and high intensity on T2WI. The brain stem had shifted dorsally. Rich feeding to the lesion from the ethmoidal artery was seen on angiography. An operation was performed using an extensive transfrontal approach. After bifrontal craniotomy, orbitofrontal osteotomy was performed. This approach enabled us to minimize frontal lobe retraction, to interrupt the blood supply to the tumor early, and to remove the tumor completely from the frontal base and to present invasion of the sinuses. The postoperative course was uneventful without cosmetic problems.