Cholesteatoma is a skin-related otologic disorder. The histologic and electron microscopic findings in a human cholesteatoma matrix have been studied in detail.1The cellular composition of the matrix and its adjacent mucosal lining is, however, not static but undergoes permanent changes in terms of cells moving from the circulation into and out of this area. Migrant lymphoid and nonlymphoid cells (Langerhans' cells, monocytes) presumably play a key role in the natural history of the disease. This constant local cell traffic indicates that an aural cholesteatoma is a much more dynamic disease entity, on a cell biologic level, than has ever been assumed before. Our new data, obtained by analyzing human cholesteatoma biopsy specimens, external ear canal skin, and normal tympanic membranes with modern (immuno-) histochemical tools—by application of so-called monoclonal antibodies to cell-membrane receptors and tissue components—should be placed against the background of observations recently made in immunodermatology and lymphoid tissue research.2,3