NF1 and neoplasm: However, phenotypic switching during tumour progression can cause loss of typical immunophenotypic features, such as Melan-A, HMB45, S100, and SOX 10.12,13 In such cases, molecular testing for melanoma-related mutations like BRAF, NRAS, and NF1 may be necessary.13 For our patient, the diagnosis was confirmed by histopathological findings and the typical immunohistochemical profile, without the need for further tests.