Report of a Case of Middle Ear Adenoma

Abstract

Middle ear adenoma (MEA) is a distinctive, rare entity that appears to be derived from the epithelium of the middle ear mucosa.
A 39-year-old woman came to Mitsui Memorial Hospital, complaining of right tinnitus and ear fullness. Her right tympanic membrane was swollen by a middle ear mass lesion, and imaging studies such as CT and MRI of the temporal bone demonstrated a middle ear tumorous lesion that extend expansively. She did not feel otalgia or vertigo, and there was no otorrhea, facial palsy, nor facial spasm. Her right audiogram showed slight hearing loss (Pure tone average: 25.0dBHL) and her right tympanogram was Type B or C1. Thus, we performed a right ear operation. At surgery, a soft yellowish tumor was found in the middle ear from the promontory, which adhered closely to the tympanic membrane, but had not destroyed the ossicles or tympanic membrane. The facial canal was intact. The tumor was removed without complication. A frozen-section diagnosis could not exclude the possibility of carcinoma, but the symptoms and signs strongly suggested a benign tumor, so we performed tumor removal and Type III tympnoplasty. The histological features and immunochemical study of the tumor showed neuroendocrine differentiation with no sign of malignancy. The postoperative course was uneventful, with no evidence of recurrence 17 months after surgery.