There was a H/O decreased hearing and tinnitus on the left side with headaches.
There is evidence of an extra-axial mass lesion located in the cerebellopontine angle cistern with an intracanalicular component. This lesion is of intermediate signal intensity on the T1W images and enhances intensely after contrast administration.
They account for approximately 7% to 8% of all primary intracranial tumors. They usually arise from the vestibular portion of the eighth cranial nerve. When bilateral, they are usually associated with neurofibromatosis type II. They usually involve the intracanalicular portion of the nerve (20% do not have an intracanalicular component). A mass may also be seen in the cerebellopontine angle cistern.
MRI:
On the T1W images, the lesions are usually hypointense or of intermediate signal and show variable signal pattern on the T2W images. They are usually well demarcated from CSF, more so on the MR cisternogram images. Cystic and hemorrhagic changes are more commonly seen, than in meningiomas. Focal/nodular calcifications may be seen. Widening of the internal auditory canal may be seen. The lesion usually shows homogeneous contrast enhancement. Occasional inhomogeneous contrast enhancement may be seen. Tumors without an intracanalicular component may be difficult to differentiate from a meningioma.
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