We report a rare case of chronic expanding hematoma in the right temporal region that developed into a large mass during 12 years. The patient, who had a history of blunt trauma in her right temporal region at the age of 4 months, noticed a slowly growing mass at the same site in the last few months. Computed tomography revealed a well-circumscribed subcutaneous tumor. The tumor was completely resected. Histopathologically, this tumor was confirmed in the diagnosis of chronic expanding hematoma.