It presents diagnostic criteria that are not yet consolidated in the literature due to its variable morphological, immunohistochemical (IHC), and genetic pattern, which is not yet fully elucidated.2, 3 Thus, this case demonstrates an evolution of NF1-related MPNST, the diagnostic difficulties, as well as the role of the dermatologist in the final diagnosis of the neoplasm. This evidence concerns the gene NF1 and malignant peripheral nerve sheath tumor.