Case Report: Synchronous lingual osseous choristoma and suprahyoid thyroglossal duct cyst: insights into the embryological thyroglossal-hyoid axis

초록

Lingual osseous choristoma is an exceedingly rare benign lesion characterized by the presence of mature bone tissue within the soft tissue of the tongue, where osseous structures are not normally found. Thyroglossal duct cysts (TGDCs) are common congenital midline neck lesions resulting from incomplete involution of the thyroglossal duct during embryogenesis. Both entities share a common embryological pathway extending from the tongue base through the hyoid bone to the lower cervical region. However, the synchronous occurrence of a lingual osseous choristoma and a suprahyoid TGDC in a single patient has rarely been reported. A 26-year-old woman presented with a slowly enlarging posterior tongue mass and a persistent foreign-body sensation during swallowing. Intraoral examination revealed a firm, pedunculated lesion covered by intact mucosa at the midline posterior tongue near the circumvallate papillae. Contrast-enhanced cervical magnetic resonance imaging incidentally demonstrated a well-circumscribed cystic lesion posterior to the hyoid bone, suggestive of a suprahyoid TGDC. Under general anesthesia, the lingual mass was excised via an endoscope-assisted intraoral approach, followed by transcervical excision of the TGDC with partial segmental resection of the hyoid bone and en bloc removal of the thyroglossal duct tract extending approximately 5 cm superiorly. Histopathological examination confirmed the diagnosis of lingual osseous choristoma, showing mature lamellar bone covered by stratified squamous epithelium, and a thyroglossal duct cyst with characteristic cyst wall features. The patient recovered without complications, with intact swallowing function and no recurrence at 18 months. This case suggests that lingual osseous choristoma and suprahyoid TGDC may represent dual manifestations of residual mesenchymal tissue along the thyroglossal duct-hyoid embryological axis, giving rise to osseous and cystic lesions at distinct anatomical levels. These findings raise the possibility of an embryological link between posterior lingual osseous lesions and the thyroglossal duct system, highlighting the need for thorough imaging of the entire thyroglossal tract when encountering osseous lesions of the tongue base.

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