Ganglioneuroma of the internal auditory canal: a case report.

Ganglioneuroma is a rare, benign, slow-growing tumor thought to develop from cells of neural crest origin, even though hypotheses on the pathogenesis of that lesion differ. Ganglioneuromas, which do not release excessive catecholamine or steroid hormones, develop primarily in the posterior mediastinum and retroperitoneum. Because of their slow growth, many ganglioneuromas are large when they are diagnosed. In this case report, a 50-year-old woman with hearing loss is described. Magnetic resonance imaging revealed a mass (3 x 4 mm) in the internal auditory canal (IAC). The encapsulated tumor was entirely excised via the middle fossa approach. The results of histopathological examination indicated that the excised lesion was a ganglioneuroma. To our knowledge, this is the first report of a ganglioneuroma of the IAC. We suggest that ganglioneuroma be considered in the differential diagnosis of all tumors of the IAC.