title: [Cholesteatoma formation in an ear fistula--model of the development of genuine cholesteatoma?].
abstract: A 20-year-old patient had developed a cholesteatoma in the depth of an ear fistula. Fistula and cholesteatoma had formed a canal in the mastoid bone running parallel to the outer ear canal and behind it, being of almost the same size. This canal ended in a "blind alley" merely fractions of a millimeter lateral of the attic without establishing contact to the middle ear. Histologically, ceruminal glands could be demonstrated in the tissue layer of the fistula. A possible interpretation is that this fistula represents remnants of a duplication of the outer ear canal. The development of "genuine" cholesteatomas out of cases similar to this one is discussed--when the cholesteatoma reaches the middle ear behind an intact drum.
mesh_terms: D000328:Adult; D002781:Cholesteatoma / Q000473:pathology*; D004424:Ear Canal / Q000473:pathology; D004427:Ear Diseases / Q000473:pathology*; D004431:Ear, External / Q000473:pathology; D005260:Female; D005402:Fistula / Q000473:pathology*; D006801:Humans; D008416:Mastoid / Q000473:pathology
vernacular_title: Cholesteatomentstehung in einer Ohrfistel--Modell einer Entwicklungsmöglichkeit des "Genuinen" Cholesteatoms?