[Immunohistochemical and clinical features of patients with benign middle ear tumors]

The middle ear is a rare site for benign tumors. We report six patients with benign middle ear tumors surgicaly removed: three with carcinoid, one with adenoma, and two with paraganglioma. These tumors showed similar histological features in trabecular and glandular architecture, so further immunohistochemical study was needed to make a definitive histopathological diagnosis. When we analyzed clinical features of patients diagnosed immunohistochemically, the differentiation of two patients with paraganglioma from the remaining four with adenomatous tumors such as adenoma and carcinoid was relatively easy from otomicroscopic findings and enhancement in temporal bone MRI. It was however difficult to differentiate patients with adenomatous tumors from each other because they induced similar clinical symptoms and showed similar findings in images. For a definitive diagnosis, it is necessary to conduct exploratory tympanotomy or removal of the tumors to obtain enough specimen for histological and immunohistochemical studies. Tumors induced no bone destruction or complications. We recommend staged operations for total removal of tumors and for good postoperative hearing.