Parapharyngeal meningioma extending from the intracranial space

A 50-year old woman with a giant parapharyngeal meningioma extending from the intracranial cavity was admitted to our hospital. The parapharyngeal tumor was biopsied using the transoral approach, and a histological section diagnosis suggested meningioma. Thereafter, further examination by magnetic resonance images (MRI) and contrast enhanced CT scans revealed a diffuse meningioma en plaque in the posterior fossa. Invasion extended from the clival dura to the right sigmoid sinus. The extracranial extension of a meningioma is very rare but a few cases have been reported. In almost all of the reported cases, a large intracranial meningioma was simultaneously or previously verified by CT scans. Our case was special in that the intracranial mass was not voluminous but showed en plaque extension, and also because the pathway of the extracranial extension through the jugular foramen was clearly visualized by CT and MRI. Obliteration and invasion of the right sigmoid sinus and the internal jugular vein by tumor were also demonstrated. (orig.)