TBX1 and neoplasm: Brachyury has been identified as a key transcription factor in the early phase of posterior mesoderm development, which includes the development of hemangioblasts and the notochord.3,13,14 Brachyury was recently established as a highly sensitive and specific immunohistochemical marker of notochordal differentiation, and it has enabled the accurate diagnosis of notochordal tumors by differentiating them clearly from other histological mimics.11–13 Although the tumor was brachyury positive in our case, the positive signal was only focal.