The pathogenesis of acquired cholesteatoma of the human middle ear: support for the migration hypothesis.

ABSTRACT

HYPOTHESIS: That acquired cholesteatoma of the human middle ear and mastoid process can be caused by migration of squamous epithelium from the tympanic membrane. OBJECTIVE: To provide histologic evidence in humans of the potential for medial epithelial migration toward the middle ear. BACKGROUND: The origin of cholesteatomas of the middle ear complex of humans is still not clearly understood. The most popular theory, the medial migration of squamous epithelium from the external auditory canal/tympanic membrane through a perforation of the tympanic membrane to form a cholesteatoma, was first proposed over a century ago independently by Bezold (1899) and Habermann (1899) based on their observations during surgery. Neither author had histologic proof. Despite much experimental efforts in animals, histologic evidence in the human continues to be the missing link. METHOD: We examined the histologic sections of the temporal bones of 60 children aged 1 day to 12 years with evidence of acute otitis media. We present our findings in the temporal bones of 3 infants. RESULTS: We find evidence of the propensity of the squamous epithelium of the tympanic membrane particularly in the pars flaccida to become very active and to migrate medially toward the middle ear. CONCLUSION: Our concept is that this material supports the migration theory that cholesteatomas are formed by the medial migration of the stimulated squamous epithelium of the tympanic membrane.