| SKULL BASE REGION | Meckel’s cave |
| HISTOPATHOLOGY | Schwannoma |
| PRIOR SURGICAL RESECTION | No |
| PERTINENT LABORATORY FINDINGS | N/A |
Case description
The patient reported facial neuralgia and paresthesia in the left ophthalmic/V1 branch that slowly progressed over several years. Imaging was suggestive of trigeminal schwannoma ( Figure 9.44.1 ). Stereotactic radiosurgery (SRS) was performed to stop tumor growth ( Figure 9.44.2 ).
| Radiosurgery Machine | Gamma Knife – Icon |
| Radiosurgery Dose (Gy) | 12 at the 50% isodose line |
| Number of Fractions | 1 |
Initial MRI 6 months prior to stereotactic radiosurgery.
Axial postcontrast T1-weighted image (left) showing the treatment plan (yellow line) . Coronal T2-weighted image (right) showing the tumor location in Meckel’s cave, treatment plan, and distance between the chiasm and the 8-Gy isodose line.
| Critical Structure | Dose Tolerance |
|---|---|
| Optic pathway | < 0.01 cc > 8 Gy |
| Brainstem | < 0.01 cc > 15 Gy |
| Cranial nerves in cavernous sinus | Unknown but significantly more resistant than optic nerve |
| Cavernous carotid artery | Very tolerant |
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