Middle Fossa Meningioma with Extracranial Extension: Staged Surgery Combining Transcranial and Endonasal Surgery

Background: Intracranial meningiomas extending into the infratemporal fossa are uncommon. Meningiomas originating from the anterior clinoid process and medial sphenoid wing have an increased tendency to extend to the extracranial region. It is difficult to accomplish complete resection, and they have a high rate of recurrence. Lateral skull base approach is the standard approach for the surgical treatment of these extensive meningiomas, but modification of the endonasal trans-sphenoidal approach that allows additional exposure of the ethomoid sinus and the orbital apex also have been used for various cranial base lesions. We present a case of middle cranial fossa meningioma extending transcranially to the infratemporal fossa and the paranasal sinus; the patient underwent staged surgery combining lateral skull base surgery and endoscopic-endonasal surgery.

Case: A 31-year-old man presented with headache and hearing impairment. MR image showed a large isointense mass in the left middle temporal fossa, extending to the infratemoral fossa, the cavernous sinus, and the paranasal sinus including the sphenoid sinus and ethomoidal sinus transcranially. He had a history of pediatric acute lymphocytic leukemia, and underwent whole-brain radiation therapy 17 years ago. At first he underwent surgery with a lateral cranial base approach (infratemopral approach) and the tumor was located in middle temporal fossa, the infratemporal fossa, and the lateral sphenoid sinus. Pathological diagnosis was atypical meningioma with the highly aggressive feature of a high mitotic index and a high proliferative index. One week later, endoscopic-endonasal surgery was performed for the resection of the residual tumor in the sphenoidal sinus and the ethomoidal sinus. The tumor was resected except within the cavernous sinus. The patient had a minimum neurological deficit of mild facial numbness after these operations and returned to his normal daily activity.

Conclusion: A multistaged surgical strategy combining a transcranial skull base approach with endoscopic-endonasal approach may be useful for the treatment of complex cranial base meningiomas showing an extracranial extension, such as a paranasal sinus and an infratemporal fossa. Endoscopic-endonasal surgery could be one of the options for the treatment of central skull base lesions, not only pituitary tumor but also meningiomas and chordomas.