A Case of Middle Ear Adenoma
A 17-year old male presented with a two-year history of tinnitus and intermittent bloody otorrhea in the left ear. He had no definitive abnormal findings based on his past medical history. He had no accompanying symptoms such as otalgia, dizziness or facial paralysis.\nThe right tympanic membrane was normal. The left tympanic membrane was not perforated but was observed as having a milky-white, middle ear polyp which has approximately 3/4 of the eardrum protruded ().\nPure-tone audiometry showed normal hearing in the right ear and mixed hearing loss in the left ear with a 32-dB air-bone gap and a 37 dBHL air conduction threshold. Temporal bone CT findings showed a pneumatized mastoid cavity, although there was a soft tissue density which caused the eardrum to protrude outwardly, and filling of the inside of the mastoid antum, middle ear, and the epitympanum was observed. No structural damage of the ossicle, facial canal or lateral semicircular canal was identified ().\nAs left middle ear tumor or congenital cholesteatoma was suspected, we performed intact canal wall mastoidectomy with tympanization. According to the operative findings, a grayish-white multilobular mass and granulation tissue fully filling the mesotympanum, epitympanum, and mastoid cavity were detected (). The multilobular mass and granulation tissue were adjacent to the ossicle, although there was no ossicle erosion, and the hypotympanum and orifice of the Eustachian tube were preserved. No mass invasion into the sinus tympani was observed. Intact canal wall mastoidectomy was then performed, and the mass inside the epitympanium was excised by removing incus.\nTissue biopsy was performed to confirm the safety margin at the outer surface of the tympanic membrane which protruded to the external auditory canal because of the mass, mucosa of hypotympanum and epitympanum.\nIn these tissues, no tumor cells were observed. Ossiculoplasty to restore hearing was not performed. Rather, a temporalis muscle facial graft was performed.\nPostoperative histopathologic results revealed a small, round-cell tumor composed of even-sized, globular cells with plenty of eosinophilic cytoplasm arranged in a platy structure. There were no findings of mitosis, necrosis or dysplastic were.\nTo obtain the differentiation diagnosis of small, round-cell tumor, immunohistochemistry was performed. Based on the findings which were negative to the Ki-67 antigen, positive to synaptophysin, mildly positive to CD56, negative to chromogranin, and negative to S-100 protein, middle ear adenoma was diagnosed ().\nIn the three weeks following surgery, all of the packing material in the external auricular canal was removed, and two months after the surgery, the eardrum was well-grafted and stabilized. Two and seven months after surgery, temporal bone CT and pure tone audiometry were both performed. Pure-tone audiometry showed 8 dBHL of the left bone conduction threshold and 32 dB of the air conduction threshold, both of which were similar to the patient's preoperative hearing level, however, the patient's tinnitus had improved. According to the temporal bone CT performed seven months after the surgery and otoscopy which was performed two years following the surgery, there was no evidence of recurrence.