Immunohistologic analysis of the cholesteatoma matrix in children.

The immunohistological characteristics of retraction pockets, cholesteatoma matrix and granulomatous tissue were compared in 14 samples from pediatric cholesteatoma. The junction between epidermis and the middle ear mucosa appeared as the most inflammatory area, displaying the characteristics of delayed type hypersensitivity. CD1 + Langerhans cells were observed in all epidermic areas, but expressed class II molecules only in the vicinity of polymorphonuclear infiltrates. Numerous mast cells and IgA producing cells were also observed, suggesting that defenses from the mucosal immune system are summoned and contribute to the pathogenesis of cholesteatoma.