Mechanisms of retraction pocket formation in the pediatric tympanic membrane.

The epidemiological nature of acquired cholesteatoma in children has shown that it occurs more often in the posterosuperior quadrant of the pars tensa and in the pars flaccida. This type of cholesteatoma is rarely seen before the age of 3 years, and serous otitis media is the most important risk factor for its occurrence. In an attempt to present a pathological rationale for these clinical findings, tympanic membranes from 11 temporal bones with purulent otitis media and 13 with serous otitis media were evaluated light microscopically and compared with 14 temporal bones without disease. Ages ranged from newborn to 3 years 6 months. The persistence of mesenchyme and greater inflammatory reaction observed in the pars flaccida and the posterosuperior quadrant of the pars tensa and changes in collagen and elastin observed in purulent otitis media and serous otitis media may represent a pathological rationale for the epidemiological nature of cholesteatoma in children.