Primary acquired and recurrent cholesteatoma versus residual cholesteatoma. A light- and electron-microscopical study.

A comparative morphological study was performed between the primary acquired and recurrent cholesteatoma on the one hand and the residual type on the other. Between these two groups of cholesteatomas, one can distinguish differences in the pathogenesis and clinical features which may have therapeutic implications. This study, based on light- and electron microscopy, revealed no essential differences in morphology between the two groups of cholesteatoma. In particular, infiltration of matrix into subepithelial tissues could be found in cholesteatoma both with and without signs of inflammation or infection in the perimatrix, and this phenomenon could be applied to both types of cholesteatoma. This morphological uniformity suggests that the differences in clinical features and pathogenesis should not influence the otologist's choice of therapeutic approach. The results of this study emphasize the importance of removing as much as possible of the adjacent subepithelial tissue during eradication of the cholesteatoma, regardless of clinical type of cholesteatoma or signs of infection.