Spinal Clear Cell Meningioma: Clinical Study with Long-Term Follow-Up in 12 Patients

BACKGROUND: Clear cell meningioma (CCM) is a rare histologic subtype of meningioma. The features of CCMs have commonly been based on intracranial cases. However, CCMs in the spinal cord are even rarer, and their natural history, management, and prognosis remain ill-defined. METHODS: From January 2006 to January 2018, 12 patients with spinal CCM were treated in our hospital. The clinical features, radiologic findings, diagnosis, treatment, and outcome of these patients were analyzed retrospectively. Additionally, we performed a review of the reported data on spinal CCMs. RESULTS: CCMs accounted for 2.8% of all the spinal meningiomas treated in our hospital. The most common localization of this disease was the lumbar region (7 of 12). The mean age at diagnosis was significantly younger than that of patients with spinal meningiomas (28.8 +/- 13.4 years vs. 54.0 +/- 14.4 years). During the follow-up period, 5 patients (41.7%) experienced tumor recurrence. Kaplan-Meier analysis showed that younger patients had a significantly shorter progression-free survival time than older patients. The review of the reported data showed that 55 cases of spinal CCMs had been reported. Nineteen patients (38.0%) had developed local recurrence, with a 5-year progression-free survival rate of 33.3%. CONCLUSIONS: Spinal CCMs are extremely rare tumors with a predilection to affect younger patients and have a high recurrence rate. Although gross total resection is considered to be the optimal treatment, radiotherapy could be considered for patients who had undergone subtotal resection or for younger patients, regardless of the extent of removal. Close follow-up of the entire neuraxis for years is crucial.