Middle ear adenoma: a case report with ultrastructural findings.

A 56-year-old woman presented with unilateral tinnitus and hearing loss for 18 months. A middle ear mass was detected clinically. At operation, the tumour was found to have eroded the stapes. The light and electron microscopic features of the tumour were those of a middle ear adenoma. This rare benign tumour has an excellent prognosis. Erosion of an ossicle has not been previously associated with this tumour. Benign adenomatous tumours arising from middle ear mucosa are rare (Mills and Fechner, 1984). The term adenoma of middle ear was proposed by Hyams and Michaels (1976), and their review of 20 cases emphasized the benign behaviour of these tumours. We report a case of middle ear adenoma in which ossicular erosion occurred.