MR findings of an unusual intracranial neuroma simulating a meningioma.

We report an unusual intracranial neuroma that simulated a meningioma on CT and magnetic resonance imaging. A diagnosis of meningioma was suggested because the tumor was tentorium-based; had enlarged into both the middle and posterior fossae; contained calcification and was homogeneous and densely enhancing on contrast CT; and was isointense with brain on T1- and T2-weighted images. The tumor proved to be a schwannoma with characteristic electron microscopic findings.