NF1 and neoplasm: After multivariate analysis, however, only NF1 (P = .007) and tumour volume more than 200 m (P = .015) remained independent predictors of poor outcome.We recommend that NF1 be taken into account during MPNST staging.As the survival rate in the NF group was dependant on tumour volume, routine screening of these patients with FDG PET and/or MRI may be warranted, thereby staging and controlling them at the earliest possible opportunity.