A Clinicopathologic Study of Head and Neck Malignant Peripheral Nerve Sheath Tumors

AbstractHead and neck high grade malignant peripheral nerve sheath tumors (HN-MPNSTs) are rare highly aggressive soft tissue sarcomas that show overlapping morphologic and immunophenotypic features with melanoma and other high grade sarcomas, resulting in diagnostic challenges, particularly in sporadic settings. Recent discoveries have implicated loss of function mutations in the polycomb repressive complex 2 (PRC2) components, includingEED orSUZ12 genes, as one of the leading pathogenetic mechanisms in high grade MPNST. MPNSTs with PRC2 loss are associated with complete loss of trimethylation at lysine 27 of histone H3 (H3K27me3), which emerged as a reliable immunohistochemical marker in the diagnosis of sporadic and radiation induced MPNST. As the diagnosis of MPNST in the HN is particularly challenging to distinguish from melanoma and other sarcoma types, we carried out a clinicopathologic analysis on HN-MPNST patients managed at our institution over a 20-year period (1997 –2016), using the latest diagnostic criteria including H3K27me3 staining and other molecular investigations. The overall survival of HN-MPNST was compared with other HN soft tissue sarcomas. The diagnosis of HN-MPNST was confirmed in 13 patients (seven males and six females), with a mean age of 31 years; with 3 (23%) patients being of pediatric age. The most common site was the neck soft tissue (77%). Two-thirds of patients (n = 9) had stigmata of NF1, three had prior radiotherapy and only one deve...
Source: Head and Neck Pathology - Category: Pathology Source Type: research