Petrous ridge meningioma

Case contributed by Ian Bickle


Right side trigeminal neuralgia. Space occupying lesion?

Patient Data

Age: 45 years
Gender: Female

3.4 cm enhancing convex mass with underlying bony irregularity adjacent to the right petrous ridge.  

The mass covers the right internal auditory meatus.

The 4th ventricle is effaced as it the brainstem, due to mass effect.

The supratentorial brain is normal.


3.4 cm avidly and homogenously enhancing convex mass with a broad meningeal attachment to the inferior aspect of the tentorium cerebelli and the adjacent petrous ridge. The mass covers the right internal auditory meatus and extends 1.4 cm into the auditory canal, but without overt expansion.

Thin dural tail. No internal cystic change within the mass.

Moderate amount of mass effect of the brainstem, cerebellum and inferior aspect of the midbrain. The mass also contacts and displaces the right trigeminal nerve.

Mild displacement and effacement of the fourth ventricle.  Mild hydrocephalus.

Case Discussion

Large mass at the right IAM, with a dural tail and MRI characteristics of a meningioma.

Meningiomas commonly occur at a multitude of sites - this being one of the less common sites.

A chief differential at this site would be a vestibular schwannoma.

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