Ultrastructural alterations of the tympanic membrane in retraction pockets from patients with chronic otitis media

Chronic otitis media with a retraction pocket is one of the forms of chronic otitis media that predisposes to cholesteatoma. The aim of our study was to determine the extent and type of changes in the tympanic membrane fragments which were surgically excised from the retraction pockets of 20 patients treated for cholesteatoma and/or hearing loss. Material evaluation and photographic documentation were performed using a transmission electron microscope (JEM 1200EX II, Jeol, Japan). We found that the morphological changes of the tympanic membrane are particularly related to the structure of the external epithelium, formation of epithelial invaginations, atrophy of the basement membrane of the eardrum and loss of circular and longitudinal collagen fibers. Ultrastructural changes in the tympanic membrane suggest inflammatory processes, epithelial migration, destruction of collagen fibers and autophagy, which indicates that the process of retraction pocket development is active. Tympanic membrane retraction pocket development is an active process, not the sequela of prior illness. The intensification of the keratinization and migration process of the epithelium layer confirms one of the theories of the creation of cholesteatoma and shows that the retention pocket is a pre-cholesteatoma condition.