A case of schwannoma arising in the temporalis muscle is reported. A 55-year-old woman with a painless mass in the left temporal region was referred to our department by her otolaryngologist because of a suspected diagnosis of erectile hemangioma, based on the results of angiography. She had recognized the mass 6 years before her initial visit. On presentation, the mass measured 20 × 10 × 5 mm at rest and it increased in size to 37 × 22 × 10 mm in clenching position. Imaging studies, including CT, MRI, and ultrasound, could not confirm the diagnosis. Initially, she did not consent to undergo surgical resection, and the mass was followed for several years. Four years after presentation, the mass had increased in size to 43 × 33 × 15 mm at rest, and the patient consented to surgical removal. The mass was approached via a preauricular incision, extending to the temporal region. Since the mass was a yellowish encapsulated tumor, a suspicion of hemangioma was ruled out on intraoperative diagnosis. The resected tumor was diagnosed as schwannoma pathologically. Microscopically, the tumor included various stages of degradation, such as myxoid changes and cystic cavity formation, as well as an abundance of small vessels. There has been no sign of recurrence during 5 years of follow-up.
