We report here on a case of a neurogenic tumor of the neck with an uncertain origin on the preoperative evaluation. A 67-year-old woman with a palpable mass in the left side of the neck was referred to our hospital. The mass had slowly grown over 7 years and her dyspnea had gradually become more severe over the recent 6 months. Computerized tomography and magnetic resonance imaging showed an 8 cm sized solid mass that abutted the trachea and the esophagus without invasion, but the origin of the mass was not clearly identified. During surgical exploration, we identified that the tumor was located in the esophageal muscle layer. Immunohistochemical staining revealed that the tumor cells were positive for S-100 protein, which confirmed a diagnosis of schwannoma.