The Management of Trigeminal Schwannoma: A Single-Institution Experience of 49 Cases

Introduction: Trigeminal schwannomas are benign intracranial tumors that can originate from any point along the course of the trigeminal nerve. Depending on their size and location, these tumors may cause a wide range of symptoms, and their variability necessitates tailored management, which may include observation, pharmacological therapy, surgery, and radiotherapy. Given their potential to extend from the trigeminal nerve's origin to its distal extracranial branches, multiple classification systems have been devised to categorize these tumors, including the Yoshida and Kawase classification. Trigeminal schwannomas are the second-most-common type of intracranial schwannoma and are often associated with neurofibromatosis type 2. Despite their prevalence, there remains a dearth of research on the presentation and management of these tumors. This descriptive case series explores 49 patients with trigeminal schwannomas who presented to a large academic medical center.

Methods: We conducted a single-center retrospective review of patients aged 18 years and older who presented to the department of neurological surgery. A total of 64 patients diagnosed with schwannoma were initially considered for the study. 15 patients were excluded due to nontrigeminal origin or age less than 18 years, and the medical and imaging records of the remaining 49 patients were included for analysis. Patients’ demographic information, clinical presentation, tumor characteristics (size, Yoshida and Kawase classifications at diagnosis, location, growth over time), management strategies, and associated complications were assessed.

Results: Among the 49 patients included in our study, the female-to-male ratio was 1:1.04 (n = 25, 51% and n = 24, 49%, respectively). Nine (18.37%) patients presented with neurofibromatosis type 2 (NF2), with a mean age of 43.6 years. A substantial portion of patients (n = 23, 46.94%) had tumors smaller than 2 cm, primarily located in the middle fossa (n = 21, 42.86%) or extending across both the middle (n = 10, 20.41%) and posterior fossa or only in the posterior fossa (n = 10, 20.41%). Management strategies varied, with 29 patients (59.18%) managed conservatively through observation, 16 (32.65%) undergoing microsurgery, predominantly via the retrosigmoid approach (n = 4, 23.53%) followed by pterional (n = 4, 23.53%) and combined approaches (n = 4, 23.53%), resulting in 10 gross total resections (52.63%), and 33 (67.35%) receiving radiation therapy. Eight patients were prescribed carbamazepine, and one oxcarbazepine (16.33% and 2.04%, respectively) for treatment of associated trigeminal neuralgia. Among the 20 patients who underwent a mean 6 year (75 months) follow-up with postoperative MRIs, 17 (85.00%) experienced an increase in tumor size.

Conclusion: This study represents a large series of trigeminal schwannomas and describes the variable presentation and treatment strategies used to manage these tumors. Management is often driven by numerous patient- and tumor-dependent factors, as well as clinician preference. In our opinion, subtotal resection aimed at preserving function is a valuable strategy for management of large, growing and/or symptomatic tumors but does come with a higher risk of need for additional intervention.

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Publication History

Article published online:
05 February 2024