[Comparison of computed tomographic scanning and magnetic resonance imaging in the diagnosis of trigeminal schwannoma. Report of four cases].

Four cases of trigeminal schwannoma with different clinical presentations are reported. Two patients had root-type tumors and two ganglion-type tumors. Computed tomography demonstrated the mass in each case, but extension of the tumor into Meckel's cave, displaced but uninvolved seventh and eighth cranial nerves, extension of the tumor into the orbit or into the infratemporal fossa, and other anatomical details were far more clearly shown by magnetic resonance imaging, which provided confirmation of the mass lesions in the base of the brain and within the posterior fossa.