RESUMO
BACKGROUND: Mature teratoma composed of all three basic germ cell layers of the head and neck is a rare disease. Teratomas involving the temporal bone are particularly scarce. CASE SUMMARY: A 48-year-old male patient with a history of chronic otitis of the left ear from infancy, for which he had been operated on twice, was referred to our hospital for chronic otitis, cholesteatoma and a middle ear mass. Computed tomography (CT) scan and magnetic resonance imaging (MRI) revealed a eustachian tube teratoma, in which the anterior lower part and posterior upper part were connected by a thin membranaceous tissue. The mass was removed completely under general anesthesia by mastoidectomy. As of last follow-up (2 years post-surgery), the disease had not relapsed. CONCLUSION: Pre-operative CT and MRI are necessary for eustachian tube teratoma. Complete surgical resection provided excellent prognosis.