Pathogenesis of Attic Cholesteatoma

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In this paper, the clinical and basic studies were designed to understand the pathogenesis of attic cholesteatoma. Among 101 ears of 51 patients who had been treated at our OME outpatient clinic, the incidence of retraction pocket (RP) was 42.6% in OME group, which was statistically significantly higher than that of control (2.2%). All but one ear showed type A or Cl tympanogram, indicating normalized mesotympanum and CT scan revealed the clear attico-antrum. These findings indicated that RP persisting or developing after the resolution of OME was not caused by the disorder of surrounding structure but rather by the pars flaccida itself.
The study of the epithelial cell kinetics in the pars flaccida of the tympanic membrane revealed that epithelial cells in the pars flaccida was smallest in shape and strongest in itscell proliferation activity in the entire tympanic membrane. This observation indicated that the pars flaccida bears very active generation of epithelial cells, which is likely to produce RP under some pathologic circumstances. As a matter of fact, immunohistochemical studies demonstrated that ICAM-1, EGF receptor, IL-6 receptors, and the increased density of Ki-67 antigen were present in the epidermis of inflamed cholesteatoma. Furthermore, high concentration of IL-1 and IL-6 were measured in cholesteatoma debris by ELISA. These findings indicated that cytokines were likely to play a role in the proliferation of epidermis of the pars flaccida to form cholesteatoma.