PMEL and melanoma: While gross specimens that clearly arise from nerves lend credence to a diagnosis of MPNST, negative staining for cytokeratins and melanoma markers like Melan-A, MITF, and HMB45 can be useful in distinguishing MPNST from carcinoma and melanoma (Reinert et al., 2019; Pekmezci et al., 2015; Fletcher, 2014).