Cholesteatoma's a destructive and expanding keratinizing squamous epithelium in the middle ear and/or mastoid process. Causes There're two types: congenital and acquired. Acquired cholesteatomas can be caused by a tear or retraction of the ear drum. Usually cholesteatomas in adults are acquired through the above reasons. Less commonly the disease may be congenital, when it grows from birth behind the eardrum. Congenital cholesteatomas are more often found in the anterior aspect of the ear drum… (More on Cholesteatoma)