Benign-appearing Intraspinal Malignant Peripheral Nerve Sheath Tumors: Treatments and Outcomes of 14 Consecutive Patients

AIM: To investigate the clinical characteristics and prognostic factors that may influence outcomes of patients undergoing benign-appearing intraspinal malignant peripheral nerve sheath tumors (MPNSTs). MATERIAL and METHODS: This study included a total of 14 consecutive patients who were diagnosed with benign intraspinal tumors firstly and confirmed as intraspinal MPNSTs by pathology. The univariate analyses of various clinical factors were performed to identify variables that could predict prognosis. Endpoints were mortality and local recurrence. The survival rate was estimated using the Kaplan-Meier method, and differences were analyzed by carrying out the log-rank test. In addition, factors with p values of <= 0.05 were considered statistically significant. RESULTS: Benign-appearing intraspinal MPNSTs showed some different clinical features compared with spinal MPNSTs and intraspinal benign tumors. The present study found that age at diagnosis, Neurofibromatosis type 1 (NF-1) history, tumor sites, malignant grade, Ki-67 and tumor resection method might be factors closely associated with recurrence and survival of intraspinal MPNSTs patients. CONCLUSION: Benign-appearing intraspinal MPNSTs are relatively rare tumors with a better overall prognosis compared with common spinal MPNSTs. A lot of factors can affect patients' survival and local recurrence. These prognostic factors still require further confirmation with further studies including more patients.