Cavernous sinus/petroclival meningioma – immediate postoperative radiosurgery for residual/postoperative radiosurgery for recurrence

SKULL BASE REGION	Petroclival
HISTOPATHOLOGY	Meningioma, transitional type, WHO grade I
PRIOR SURGICAL RESECTION	Yes
PERTINENT LABORATORY FINDINGS	N/A

Case description

The patient is a woman who was diagnosed at the age of 54 with a left petroclival meningioma causing atypical trigeminal neuralgia. The tumor extended into the cerebellopontine angle (CPA) and cavernous sinus. She was initially treated with oral carbamazepine, which was not tolerated. Surgery was indicated to remove the posterior portion of the tumor and decompress the trigeminal nerve root entry zone ( Figure 6.27.1 ). Postoperatively, she suffered from mild diplopia and dizziness, but fully recovered over a 6-month period. Histology revealed a transitional meningioma, WHO grade I. Stereotactic radiosurgery (SRS) of the residual tumor in the cavernous sinus was planned and administered at 3 months after surgery ( Figure 6.27.2 ). The tumor remained stable for 5 years. The patient then reported new trigeminal symptoms. Brain magnetic resonance imaging (MRI) confirmed progression of the posterior portion of the tumor extending into the CPA ( Figure 6.27.3 ). The patient underwent SRS of the recurring tumor in the posterior fossa ( Figure 6.27.4 ).

Radiosurgery Machine	CyberKnife
Radiosurgery Dose (Gy)	Initial: 13, at the 81% isodose line Recurrence: 20, at the 82% isodose line
Number of Fractions	Initial: 1 Recurrence: 4