Treatment outcomes of 17 patients with atypical spinal meningioma, including 4 with metastases: a retrospective observational study

BACKGROUND CONTEXT: Because of the scarcity of atypical spinal meningioma, there is a lack of research on this type of tumor or its associated metastases. PURPOSE: The aim of this study was to investigate the biological behavior of atypical spinal meningioma and identify its prognostic factors by reviewing surgical and clinical outcomes of patients with these tumors. STUDY DESIGN: A retrospective chart review was performed. PATIENT SAMPLE: We retrospectively reviewed the data from all patients who underwent spinal cord tumor excision between 1994 and 2017. Seventeen patients were pathologically proven to have atypical spinal meningioma. OUTCOME MEASURES: We examined patients’ neurologic status by determining their Nurick scores before and after surgery. Moreover, imaging studies, laboratory data, and the employed surgical method were analyzed retrospectively, as was the Ki-67 index and prognosis following postoperative radiation therapy. METHODS: The ranges, locations, and pathologic diagnoses of the tumors were extracted from the radiological and pathological records of each patient. The extent of surgery and progression of disease were confirmed using postoperative enhanced magnetic resonance imaging. Patients were divided into two atypical spinal meningioma groups: primary and metastatic. The demographics, age, sex, presenting symptom duration, tumor location, Simpson resection grade, Ki-67, radiotherapy, recurrence, overall survival, and progression-free survival of patients in both groups were compared. RESULTS: Seventeen patients were included in the analysis, of whom 12 (70%), 4 (24%), and 1 (6%) had tumors in the thoracic, cervical, and sacral regions, respectively. Complete and subtotal resections were achieved in 15 (88%) and 2 (12%) patients, respectively. Overall and progression-free survival rates in patients who underwent complete resection were longer than those in patients who underwent subtotal resection (p<.001). Four patients (24%) had metastatic meningiomas in the brain, among whom three were administered adjuvant radiotherapy after surgery. Two patients with intramedullary atypical spinal meningioma had metastatic tumors and experienced poorer prognoses. The 5-year overall and progression-free survival rates were 84.4% and 85.2%, respectively. The Simpson resection grade, Ki-67 index, and preoperative neurologic status were found to be important prognostic factors on univariate Cox regression analysis (p<.05). CONCLUSIONS: Complete resection should be considered as a primary treatment modality for individuals with atypical spinal meningioma. If subtotal resection is performed, adjuvant therapy can be administered.