[Developmental anomaly of the hyoid bone: an unusual cause of dysphagia].

We report the case of a hyoid syndrome caused by a developmental anomaly of the second branchial cleft, presenting at adult age by dysphagia without any abnormality detected at the barium swallow and at naso-pharyngeal endoscopy, first examinations to perform in case of dysphagia. The MRI findings of this anomaly showed a hyperintense well-limited vallecular mass syndrome. The diagnosis of hyoid bone anomaly was established at spiral CT with 3D reconstructions showing an incurvated and elongated lesser cornua causing persistant impingement on the lateral wall of the oropharynx. CT scan performed during Valsalva manoeuver showed the persistance of the compression during pharyngeal insufflation.