Massive Stylohyoid Hyperostosis With Fusion to the Hyoid: An Extreme Variant of Eagle Syndrome

Eagle syndrome is classically defined by symptomatic elongation of the styloid process or calcification of the stylohyoid ligament. While elongated styloid processes are relatively common radiographic findings, extreme bony hypertrophy with direct involvement of the hyoid bone is exceedingly rare. We report the case of a 69-year-old male with progressive unilateral odynophagia and neck pain found to have massive hyperostosis of the left styloid process, measuring approximately 9 cm in craniocaudal length, with abutment, erosion, and fibrous union to the lateral body and greater horn of the hyoid bone. Surgical management required a transcervical parapharyngeal space approach with identification and transposition of multiple cranial nerves and major vessels, followed by excision of approximately 7.5 cm of the hyperostotic styloid process and partial hyoid resection, resulting in resolution of symptoms. This case represents an extraordinary variant of Eagle syndrome with concomitant hyoid involvement, significantly exceeding typical descriptions in the literature. Awareness of such atypical anatomy is critical for operative planning and neurovascular preservation.