[Anatomo-pathology of cholesteatoma].

The authors, from their own histopathological studies and from an overview of otological literature focus the controversial problems about the so-called disease cholesteatoma. The history of cholesteatoma has been marked out by pathologic data which, initially caused the cholesteatoma to be identified as a keratinized squamous tumor. This misnomer will however be retained because of it long-established usage. "Skin in the wrong place" in the middle ear summarizes this clinical entity. Electron microscopic observations provide arguments in favour of the migratory theory and the invasion of the epidermis from the bottom of the external ear canal into the middle ear cavity (identical fine morphology between skin and cholesteatoma, presence of Langerhans and Merkel cells, sharp junction between the advancing front of the cholesteatoma and the middle ear mucosa). Recent immunohistological techniques allow consideration of cholesteatoma as a self-induced inflammatory process in response to tissular and cellular conflicts. A cholesteatoma could be merely a non-healing wound process and a disease of epidermal growth control occurring in the middle ear space. The logical principles governing cholesteatoma surgery, suggested by these biological considerations, are: total removal of cholesteatoma matrix, prevention of cholesteatoma recurrence by a careful respect of the barrier separating the middle ear mucosa from the skin-lined bony external ear canal, maintenance of good healing conditions for both mucosa in a closed well-ventilated middle ear and epidermis in a harmonious anatomical external canal.