Cholesteatoma of the external auditory canal and keratosis obturans.

Keratosis obturans and external auditory canal cholesteatoma have often been regarded as a single entity. However, these are two distinct disorders with their own clinical presentations, physical and pathologic findings, and treatment. Keratosis obturans is an accumulation of obstructive desquamated keratin in the external auditory meatus. External auditory canal cholesteatoma is an invasion and erosion of squamous epithelium into a localized area of the bony ear canal. The origin of both entities remains obscure. The clinical symptoms, pathologic processes, and treatment are outlined and compared. Case reports are presented to illustrate the features of these two diseases.