Radiographic Association of Schwannomas With Sensory Ganglia

Objective: Clinical experience suggests that the majority of schwannomas arise within sensory ganglia, suggesting that intra-ganglionic glial cells represent a potential cell of origin for schwannomas. To support this clinical impression, we reviewed magnetic resonance imaging (MRI) studies performed over a 5-year period at our institution to determine the relationship of cranial and spinal nerve schwannomas with the ganglia of the associated nerves. Study design: Retrospective cohort study. Setting: Tertiary referral center. Patients: Patients undergoing imaging study at our institution over a 5-year period. Intervention(s): Radiographic images at our institution were reviewed as well as published studies to determine the anatomic location of schwannomas. Main Outcome Measure(s): Anatomic location of schwannomas. Results: A total of 372 patients were found over the 5-year study period, 31 of those were diagnosed with neurofibromatosis Type 2 (NF2). Vestibular schwannomas comprised the greatest number of schwannomas, followed by spinal schwannomas. In NF2 patients, spinal schwannomas were the most common tumor, followed by vestibular schwannomas. In NF2 patients and those with sporadic schwannomas, the overwhelming majority of tumors arose in nerves with a sensory component and were associated with the sensory ganglia of the nerves (562/607, 92.6%). Very few tumors arose from pure motor nerves. This is supported by review of published articles on anatomic location of schwannomas. Conclusion: Schwannomas are strongly associated anatomically with the ganglia of sensory nerves. These findings raise the possibility that intraganglionic glial cells give rise to the majority of schwannomas.