Immunohistochemically, neurofibromas show patchy S100 positivity, CD34 positive fibroblasts, and retention of intratumoral axons by neurofilament staining [32], whereas schwannomas are diffusely S100 positive and calretinin positive [33], MPNSTs often lose H3K27me3 and have variable S100 [21], DFSP is strongly CD34 positive [24], and dermal nevi express Melan A and S100 [27]. The gene discussed is CALB2; the disease is neurofibroma.