Cholesteatoma auris congenita arising from microtia.

The external auditory canal opens medial to lateral in embryonal development. It is obvious that a developmental arrest anywhere during this stage would produce an absence or discontinuity of the canal, that is, congenital atretic ear. Whether or not the obliterative tissue has a bony structure, cholesteatoma can be formed behind it. Microtia is usually associated with an atretic meatus, and it may involve the possibility of epithelial cyst or cholesteatoma. The diagnosis can usually be made by the finding of tender swelling in the deformed auricle or its surroundings. On occasions, it may become necessary to distinguish these conditions from secondary infection of an epidermal cyst on the auricular surface. Several recurrent painful swellings on the deformed auricle in spite of conservative treatment indicate the need for routine otologic radiographs.