Vestibular Schwannoma (VS)
Figure 1: The most common intracranial location of schwannoma is in the cerebellopontine angle, as in this patient. Cystic change is quite common in larger schwannomas on T2WI (left). Schwannomas are also typically avidly enhancing on postcontrast T1WI (right). This schwannoma can be differentiated from meningioma based on this cystic change and on the clearly delineated extention into the internal auditory canal. IAC remodeling and widening may also be present. The lack of a meningioma's "dural tail" is also helpful.
Figure 2: Axial T1 post-contrast images demonstrate bilateral vestibular schwannomas (top row left) and meningiomas (top row right and middle row left). Sagittal T1 post-contrast (middle row right) and T2 (bottom row) images demonstrate enhancing, expansile, centrally located intramedullary lesions within the spinal cord compatible with ependymomas in this patient with Neurofibromatosis Type II (NF-2).
Figure 3: Post-contrast T1 images (top row left – axial, top row right – coronal) demonstrate an avidly enhancing tiny in the apex of the left internal auditory canal. Heavily T2-weighted CISS sequence (bottom row) also shows this nodule and can show the nerve from which it arises. This appearance is typical for a tiny IAC schwannoma.
- Benign peripheral nerve sheath tumor arising from Schwann cells of CN 8 (vestibular portion) within the CPA-IAC
- WHO grade 1
- Originates from Schwann cells surrounding CN 8 vestibula...