Extra-axial chordoma of the gingiva.
Extra-axial chordomas are exceedingly rare malignant tumours. Herein, we present the first case of an extra-axial chordoma in the gingivae. A 21-year-old man presented with a suspected chordoma in the upper right gingiva. Diagnosis was difficult; however, owing to strong expression of the chordoma marker brachyury, extra-axial chordoma was ultimately diagnosed. The tumour was completely resected without performing a facial incision. To ensure its safety and effectiveness, the surgical procedure was simulated several times before its performance using a three-dimensional (3D) model. Twenty-four months after surgery, the patient remains disease-free. A diagnosis of extra-axial chordoma can be confirmed by immunohistochemical staining for brachyury.