An Unusual Case of Bony Styloid Processes That Extend to the Hyoid Bone

Abstract

The embryological origin of the hyoid bone is a point of uncertainty, with controversy surrounding the relative contribution of the second pharyngeal arch to hyoid development. We encountered a 52-year-old male with bilateral bony styloid extension to the lesser cornu of the hyoid bone during the workup of a patient with laryngeal cancer. This embryological malformation clearly supports the hypothesis that the second pharyngeal arch gives rise to the lesser cornu and demonstrates an unusual clinical finding that may be encountered by otolaryngologists. We demonstrate the imaging findings and surgical management of this unusual anatomical variant and review the embryological basis for this rare malformation.

Figure 1

(a) CT scan of hyoid bone-styloid process extension. CT scan of hyoid bone and styloid process in patient. Arrowhead points to styloid process. Asterisk marks hyoid bone body. Thick arrow points to area of extension between hyoid bone and styloid process. (b) Normal CT scan of styloid process and hyoid bone. Normal CT scan of hyoid bone and styloid process for comparison. Arrowhead points to styloid process. Asterisk marks hyoid bone body.

Figure 2

3D reconstruction of hyoid bone-styloid process extension. 3D reconstruction of hyoid bone and styloid process. Thick arrow points to area of extension between hyoid bone and styloid process. Asterisk marks hyoid bone body. Thin arrow points to lesser horn of hyoid bone. Arrowhead marks styloid process.