Cholesteatoma of the temporal bone.

Cholesteatoma presents a variable clinical picture with freedom from symptoms for periods of different duration. The roentgen diagnosis is based upon destruction of bone by the tumor (4). Cholesteatoma develops in a setting of chronic middle-ear infection and a poorly pneumatized mastoid. Perforation of the membrana flaccida or of the posterior margin of the pars tensa should arouse suspicion of this lesion. In response to infection the stratified squamous epithelium from the external auditory canal extends through the perforation. The mucosa is gradually destroyed and replaced by epidermal cells as a result of extension of epidermis from the external auditory canal through the ruptured drum, or by cellular metaplasia of the cuboidal-cell lining within the middle ear. The desquamated debris gradually collects and forms a constantly enlarging mass, which erodes the adjacent bone. Antibiotics have no effect on the growth of a cholesteatoma. The tegmen tympani may be destroyed, allowing the cholesteatoma to ...