Clinical, radiological, and pathological features of 26 intracranial and intraspinal malignant peripheral nerve sheath tumors
Intracranial and intraspinal malignant peripheral nerve sheath tumors (MPNSTs) are rarely reported because of their extremely low incidence. Knowledge about these tumors is poor. In this study the authors aimed to analyze the incidence and clinical, radiological, and pathological features of intracranial and intraspinal MPNSTs. Among 4000 cases of intracranial and intraspinal PNSTs surgically treated between 2004 and 2011 at Beijing Tiantan Hospital, cases of MPNST were chosen for analysis and were retrospectively reviewed. To determine which parameters were associated with longer progression-free survival (PFS) and overall survival (OS), statistical analysis was performed. Malignant PNSTs accounted for 0.65% of the entire series of intracranial and intraspinal PNSTs. Twenty-four (92.3%) of these 26 MPNSTs were primary. Radiologically, 26.9% (7 of 26) of the MPNSTs were misdiagnosed as nonschwannoma diseases. Twenty-one patients were followed up for 1.5 to 102 months after surgery. Twelve patients experienced tumor recurrence, and median PFS was 15.0 months. The 2- and 3-year PFS rates were 47.7% and 32.7%, respectively. Five patients died of tumor recurrence, and median OS was not available. The 2- and 3-year OS rates were 74.7% and 64.0%, respectively. Univariate analysis revealed that female sex, total tumor removal, and primary MPNSTs were significantly associated with a better prognosis. Multivariate analysis revealed that only total removal was an independent prognostic factor for both PFS and OS. Malignant PNST within the skull or spinal canal is a rare neoplasm and is seldom caused by benign schwannomas. Radiologically, intracranial or intraspinal MPNST should be differentiated from meningioma, chordoma, fibrous dysplasia of bone, and ear cancer. Total resection whenever possible is necessary for the prolonged survival of patients, especially males.