The epidermoid formation (Michaels' structure) in the developing middle ear.

The presence of an epidermoid-like formation located in the mucosa of the anterosuperior quadrant of the lateral wall of the developing middle ear was first described by Michaels in 1986. In a review of 41 middle ears from 20 serially sectioned fetus heads and one fetus temporal bone from our collection, six epidermoid formations were identified. Our study confirms the existence of this formation which we have decided to name Michaels' structure after Professor Leslie Michaels, the discoverer of this structure. The reasons for the different incidence of its occurrence in our series when compared to Michaels' original report, and the possible significance of Michaels' structure in the pathogenesis of congenital cholesteatoma of the middle ear are discussed.