Two cases of bilateral congenital cholesteatoma--usual and unusual presentations.

Bilateral congenital cholesteatomas are rare. We present the 8th and 9th case of this entity in the literature. One of these cases is especially unusual. In that patient an ear that had been documented as normal, both radiographically and clinically, was found to have a large cholesteatoma 18 months after the contralateral ear had been treated for the same disease. The theories of the pathogenesis of this entity are also reviewed. Our cases support several of these theories. In fact, in one of the patients, it is possible that a different etiology was involved in each ear. Incidental note is made of the fact that three of the nine reported cases of bilateral congenital cholesteatoma have occurred in the same geographic locale.