Abstract Otology 2000 B15-1

Bernard Ars MD, PhD

Consultant University Hospital Researcher University Antwerp Temporal Bone Foundation B-Bruxelles

Tympanic membrane retraction pocket as well as cholesteatoma, are both expressions of chronic middle ear disease. In case of retraction pocket, we observe a dysfunction, and in case of cholesteatoma, a bad localisation of the stratified squamous epithelium which plays a crucial role in the development of this pathology. The author evokes analyses the moment and reason for the transformation of a tympanic membrane retraction pocket into cholesteatoma. In accordance with the literature, he explains the mechanism as follows : a local additional irritation process should trigger the keratinocytes of the bottom of the bony canal, and raise the control processes which put a brake on the epithelium of the bottom of the bony canal, during his unrestrained growth forwards, into the middle ear cleft, leading to cholesteatoma.