Epidermal Langerhans cells in cholesteatoma.

The function of the epithelial component of a cholesteatoma has been the subject of intense research. The epithelium does not appear to have proteolytic enzyme activity, yet when it is present, increased amounts of bone resorption occur. Recent evidence suggests that epidermal Langerhans cells within epithelium have an immunologic alerting function. These cells were identified in normal tympanic membranes, canal skin, and cholesteatoma. The Langerhans cells in cholesteatoma displayed morphologic features similar to a contact hypersensitivity state. Langerhans cells within the epithelial matrix of the cholesteatoma may be responsible for generating and maintaining the chronic inflammatory reaction which induces bone resorption in this disease.