Middle ear neoplasms, including neurinomas, ceruminomas, carcinoids, glomus tumors, adenocarcinomas and squamous cell carcinomas, are relatively rare, and diagnosis and treatment are often difficult. Middle ear adenomas (MEAs) are even rarer, with few published reports of cases, and the classification and treatment of these tumors have not yet been established.
A 43-year-old man presented to us complaining of right aural fullness and auditory disturbance. His right tympanic membrane was swollen and white. A temporal-bone CT revealed a soft tissue shadow in the middle ear, with no evidence of destruction of the bone. The hearing level in his right ear was within normal range. We performed a right ear tympanoplasty for diagnosis and treatment. At first, we suspected middle ear cholesteatoma or chronic otitis media. However, intraoperatively, a solid tumor was found extending from the mesotympanum to the epitympanum, enfolding all of the auditory ossicles. We removed a part of the tumor to confirm the diagnosis. A frozen-section examination revealed the diagnosis of MEA. Immunohistochemical analysis of the tumor revealed evidence of neuroendocrine differentiation of the tumor, without any signs of malignancy. The patient underwent a second surgery for resection of the entire tumor, however, a residual tumor was left around the stapes. At the third operation, we used a CO2 laser to cut the superstructure of the stapes to allow any residual tumor to be removed. The postoperative course was uneventful and the patient has shown no evidence of recurrence until the present, 12 months after the third operation.
We encountered a case of MEA that was difficult to diagnose before the surgery, and it also proved difficult to remove the tumor in its entirety. The tumor was located within the middle ear, with no evidence of bone destruction, so that there was little doubt about the diagnosis of MEA, mixed type. If the diagnosis of a middle ear tumor cannot be established prior to the surgery, sufficient imaging evaluation should be conducted before the surgery. Also, the surgical procedures adopted should be determined taking into consideration the clinical findings.
