Histologically, the tumour exhibited epithelioid cytology with few physaliferous cells, but a chordoma-typical immunohistochemical profile (positive for brachyury, pan-cytokeratin, EMA, and focal positivity for S100-protein; Figure S2), leading to the diagnosis high-grade chordoma (FNCLCC Score: 3 + 2 + 0 = 5 = G2, high-grade). The gene discussed is TBX1; the disease is chordoma.