IDH1 and neoplasm: Tumor cells were positive for tumor protein 53 (TP53), cluster of differentiation (CD)117, IDH1-R132H, synaptophysin, and CD56, but negative for avian myelocytomatosis viral oncogene homolog (C-MYC), CD3, CD10, CD20, CD34, CD38, CD45, CD79a, B-cell lymphoma 2 (BCL-2), glial fibrillary acidic protein (GFAP), AE1/AE3, Olig-2, and S100 calcium-binding protein B (S100).