Congenital cholesteatomas of the middle ear in children: origin and management.

Cholesteatomas (epidermoids) of the middle ear appearing medial to a normal tympanic membrane are identified in increasing numbers of young children. The evidence that these lesions are congenital in origin includes the young mean age of presentation, the normal appearance of the middle ear mucosa in almost all cases of small lesions, normal mastoid pneumatization documented by computerized tomography, the relatively large number of children with associated minor or major congenital malformations, and the consistent 3:1 ratio of males to females with the disorder in all of the large series reviewed. A direct relationship between congenital cholesteatomas (epidermoids) of the middle ear and the epidermoid formation is supported by the position of the epidermoid formation at a histologic transition zone in the anterior superior lateral quadrant of the tympanic cavity, which is also the site of greatest occurrence of congenital cholesteatomas. The epidermoid formation may not always involute and as it expands it would be expected to become visible medial to the tympanic membrane in the anterior superior quadrant. It seems evident that as the congenital cholesteatoma expands it can block the eustachian tube; during a bout of otitis media the tympanic membrane could perforate and the cholesteatoma could become secondarily infected. The congenital cholesteatoma in this situation would be difficult or impossible to distinguish from the more common acquired type.