[Occult Shrapnell cholesteatoma].

The pathological process in the middle ear leading to a cholesteatoma arises in the tympanic membrane from the papillae of the multilayered keratinizing squamous epithelium. A prerequisite is chronic recurrent middle ear inflammation and granulation tissue in Prussak's space. Constant squamous cells within a progressively growing papilla from the stratum corneum. Finally a cholesteatoma sac appears which perforates into the middle ear cavity.