Giant trigeminal schwannoma with cavernous sinus and brainstem involvement: Multimodal imaging and multidisciplinary surgical management

Trigeminal schwannomas (TS) are rare, benign tumors originating from Schwann cells of the trigeminal nerve. These tumors typically present with progressive facial hypoesthesia, and less commonly with trigeminal neuralgia or brainstem compression in advanced cases. The case presented here involves a 48-year-old female with a medical history of well-controlled arterial hypertension, who developed progressive right-sided facial numbness over an 8-month period. Magnetic resonance imaging (MRI) with gadolinium contrast revealed a right-sided trigeminal schwannoma extending into the cavernous sinus and posterior fossa, measuring 39 × 24 mm. The tumor exhibited hypointense signal on T1-weighted images and marked hyperintensity on T2-weighted sequences, consistent with cystic degeneration. Surgical resection was performed with near-total resection, and the postoperative course was uneventful, although facial hypoesthesia persisted. This case highlights the importance of early diagnosis, multimodal imaging, and a multidisciplinary approach to managing giant trigeminal schwannomas, particularly those involving the cavernous sinus and brainstem. Key lessons learned include the role of 3D-CISS imaging in guiding surgical approach selection and the need for careful perioperative planning to optimize outcomes and minimize neurological deficits.