The radiological differentiation of acoustic neurinoma and meningioma occurring together in the cerebellopontine angle.

A patient with right hearing loss, in whom computed tomographic scanning demonstrated a mass in the right cerebellopontine angle with widening of and extension into the internal auditory canal, but with important posterior extension and broad implantation on the surface of the petrous bone, is reported. On both T2-weighted and gadolinium-enhanced T1-weighted magnetic resonance images, there were clearly two separate tumoral lesions: an acoustic neurinoma extending into the internal auditory canal and a meningioma with broad implantation on the petrous apex. These findings were confirmed at surgery.