Voluminous Cystic Trigeminal Schwannoma: Case Report and Literature Review

Voluminous trigeminal schwannomas are rare, predominantly benign growth encapsulated tumors composed of Schwann cells with controversial surgical treatment. They account for 20% to 40% of all trigeminal schwannomas and share the same imaging findings of neurinomas elsewhere. Surgery remains the treatment of choice for most lesions as long as complete excision is feasible. A 35-year-old house wife complained of a 3-month history of progressive right visual field impairment associated with headaches. Neurological examination revealed a complete cavernous sinus syndrome. CT scanning showed a voluminous cystic mass of the right parasellar compartment extending to the optic nerve and the orbit. A concomitant MRI scan revealed more exquisite anatomical details of the lesion. The patient benefitted from a subsequent CT-angiography (not included) which excluded any vascular abnormalities associated with the tumor. Surgical excision of the tumor was warranted and the patient underwent surgery a few days after admission. A pterional extradural-intradural approach combined with incision of the lateral wall of the parasellar compartment via a standard frontotemporal craniotomy was performed and pathological examination was in favor of a cystic trigeminal schwannoma. Post-operative MRI showed a complete excision of the tumor. A 2-year follow-up yielded persistent right monocular blindness. Given this typical appearance of this lesion indicative of both cisternal and parasellar compartment extension, as well as the level of controversy surrounding surgical treatment of these particular tumors; we sought to report this rare case of a voluminous cystic trigeminal schwannoma and share our humble surgical experience of dealing with these lesions. The patient was informed that non-identifying information from the case would be submitted for publication, and she provided consent.