A Rare Case of Mastoid Process Osteoma Presenting During Puberty: A Case Report

<b>Background and Clinical Significance</b>: Osteomas of the mastoid process are extremely rare tumors. In their development, they are usually asymptomatic, they can manifest with cosmetic deformity, pain, hearing loss, and weakness of the facial nerve. <b>Case Presentation</b>: We present a clinical case of a 13-year-old girl with complaints of swelling in the area behind the left pinna, which was painless but created a cosmetic defect and an unpleasant sensation. She reported no pain in the ear and no hearing loss. An otorhinolaryngological examination, an audiometry of the patient, and a computed tomography of the head, temporal bones, and middle and inner ear were performed. The test results showed that hearing was not affected, and the tumor in the area of the mastoid process was approximately 3 cm in diameter, sitting "on top" of the mastoid process. Extirpation of the osteoma was performed with a retroauricular approach. The patient had a short postoperative period without any complications. <b>Conclusions</b>: Mastoid osteomas are rare, benign, slow-growing, and frequently asymptomatic bone tumors. Other bone lesions of the mastoid region should be ruled out in the differential diagnosis. Surgery is the treatment of choice and should be performed in the presence of symptoms or for cosmetic reasons.