Treatment outcomes for hypoglossal schwannomas: insights from a single-institution experience and literature review

Abstract

Objective: Hypoglossal schwannomas (HSs) are rare benign tumors originating from Schwann cells of cranial nerve XII. While surgery has been the primary treatment, stereotactic radiosurgery (SRS) is emerging as an effective alternative. This study evaluates the clinical characteristics, treatment strategies, and outcomes of HS patients managed with SRS, resection, or observation.

Methods: A retrospective analysis was conducted on the medical records of HS patients treated at the authors' institution from 1999 to 2024. Collected data included demographic, clinicopathologic, radiological, and treatment details. Outcomes evaluated were local tumor control (LTC), progression-free survival, overall survival, adverse events, symptom resolution, and hypoglossal nerve deficits. A literature review adhering to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines supplemented the analysis.

Results: The cohort included 16 patients (63% female) with 20 HS tumors. SRS was performed in 10 tumors (50%), demonstrating superior LTC (100%) over a 4- to 17-year follow-up. Symptom resolution was observed in 86% of SRS cases, and hypoglossal nerve deficits were minimized. No severe complications were reported in the SRS group, with only grade 1 adverse events noted. Resection, performed in 7 cases (35%), was associated with significant complications, including cranial nerve deficits and higher adverse event rates. The surgery group exhibited a declining LTC over time: 83% at 2 years, 63% at 4 years, and 42% at 10 years. Observation was chosen for 3 tumors (15%) with stable outcomes during follow-up.

Conclusions: SRS provides excellent long-term control of HS with significant symptom resolution and low recurrence rates in the authors' cohort, supporting its use as a primary treatment modality in selected patients for small and medium-sized schwannomas, particularly when a minimally invasive approach is preferred.

Keywords: CNS cancer; hypoglossal schwannoma; microsurgery; neurosurgery; oncology; skull base neoplasms; stereotactic radiosurgery; surgical technique; tumor.