An unusual presentation of chordoma as a pyloric ring submucosal tumor: The first case report of a primary gastrointestinal lesion in humans.

Introduction And Importance: Chordomas are rare malignant bone neoplasms that are presumed to arise from chordal remnants in the fetal stage and typically occur along the axial skeleton. The extra-skeletal chordomas reported to date include soft tissue of the extremities and nasopharynx. Chordoma arising from the gastrointestinal wall has not been previously described.

Case Presentation: We report on a 42-year-old man with primary chordoma presenting as a gastroduodenal submucosal tumor centered on the pyloric ring. The patient was consistently asymptomatic, and the tumor was an incidental finding. However, during a follow-up at approximately 1.6 years, an increase in tumor size was identified on computed tomography (CT), and surgical resection was performed without a definite pathologic diagnosis. The patient was successfully treated with distal gastrectomy, and the histological diagnosis was a conventional chordoma. The diagnosis was confirmed via immunohistochemical staining for brachyury, pan-cytokeratin, S-100, and SOX9. Postoperative CT and magnetic resonance imaging revealed no recurrence or metastasis during the 1.5-year follow-up period.

Clinical Discussion: Primary chordomas of the digestive tract are rare. Embryologic development of the notochord does not explain the existence of remnants in the gastrointestinal wall. Moreover, notochordal remnants, as precursors of chordoma, were not identified in the current case. The gastroduodenal chordoma may not have originated from embryonic notochordal remnants but through aberrant brachyury activation without a notochordal precursor.

Conclusion: We report the first case of primary gastrointestinal chordoma in humans. The tumor was completely removed surgically, without postoperative recurrence.