Comparative Analysis of Head and Neck and Non-Head and Neck Malignant Peripheral Nerve Sheath Tumors.

OBJECTIVES: Malignant peripheral nerve sheath tumors (MPNSTs) are a group of tumors that arise from peripheral nerves or from the various elements of the nerve sheath, including Schwann cells and perineural fibroblasts. Head and neck MPNSTs (HN-MPNSTs) are rare, accounting for 8% to 16% of all soft tissue sarcomas. This study analyzes the demographic, clinicopathologic, and survival characteristics of HN-MPNSTs and establishes comparisons with MPNSTs at other body sites (other-MPNSTs). STUDY DESIGN: Analysis of population-based tumor registry. SETTING: Academic medical center. SUBJECTS AND METHODS: The SEER database (Surveillance, Epidemiology, and End Results; 1973-2012) was queried for HN-MPNSTs (324 cases) and other-MPNSTs (1680 cases). Data were analyzed comparatively with respect to various demographic and clinicopathologic factors. Disease-specific survival was analyzed with the Kaplan-Meier model. RESULTS: Mean age at diagnosis for HN-MPNST was 49.1 years, compared with 46.1 years for other-MPNSTs (P = .0169). There was a sex predilection for males in HN-MPNSTs (60.2%) versus a female predilection for other-MPNSTs (54.2%; P < .0001). Average tumor size for HN-MPNSTs was 4.9 cm, compared with 8.7 cm for other-MPNSTs (P < .0001). HN-MPNSTs were more commonly of low histologic grade types, whereas other-MPNSTs were mostly of high histologic grade (P = .0073). HN-MPNSTs had a higher 5-year disease-specific survival than other-MPNSTs (65.1% vs 57.4%; P = .0209). CONCLUSIONS: HN-MPNSTs are rare entities. This study represents the largest series of HN-MPNSTs to date. Although HN-MPNSTs and other-MPNSTs share a common histology, there are important clinical differences between the 2 groups.