Eagle syndrome is characterized by an elongated styloid process. However, the time frame over which the styloid process becomes elongated and extends is unknown. How the condition worsens over time is also unclear. To date, there has been no report describing the chronologic change that occurs in the styloid process in Eagle syndrome. We describe a 53-year-old patient with Eagle syndrome in whom the styloid process enlarged progressively over time and the elongated styloid process fused with the hyoid bone. The styloid process was resected via a transcervical approach, and the patient's subjective symptoms improved. This is the first report showing how the styloid process can enlarge over a few years in a patient with Eagle syndrome. Surgical resection via a transcervical approach is an appropriate treatment for a patient in whom the styloid process has become excessively enlarged and elongated.