Prognostic value of histopathologic grading of sporadic and neurofibromatosis type 1-associated malignant peripheral nerve sheet tumour: need for a novel grading system?

Introduction: Histopathological diagnosis of malignant peripheral nerve sheat tumor (MPNST) remains a challenge because of the rarity of the tumour entity, its variation in histomorphology, the lack of specific immunohistochemical markers and possible sampling errors at operation. Methods: We compared retrospectivley clinical course and histopathology of 52 sporadic and NF1-(neurofibromatosis 1) associated MPNST. 14 sporadic cases (8 female, median age at diagnosis 60.6 years) and 37 NF1 associated tumours (16 female, mean age at diagnosis 26.5 years). Results: NF1 patients were found to be significantly younger…