ABSTRACT
<p><b>OBJECTIVE</b>To explore the deep pathogenesis of acquired cholesteatoma.</p><p><b>METHODS</b>The temporal bone slides of 12 ears with retraction pocket were histopathologically studied under microscope, especially focusing on the location of retraction pocket and inflammatory pathology in the local middle ear cavity next to retraction pockets. The temporal bone slides of 11 ears with acquired cholesteatoma were histopathologically observed and 33 cases diagnosed as acquired cholesteatoma were clinically observed observed in the local middle ear cavity next to the part without retraction pocket of eardrum. The results of pathological observation of the temporal bone slides with acquired cholesteatoma and clinical observation during operation for acquired cholesteatoma show that cholesteatoma invade mainly and occupied the ossicular chain eara of the middle ear cleft.</p><p><b>CONCLUSION</b>In the pathological process of otitis media, the intractable pathological changes in the ossicular chain area can inward adhere posterosuperior quadrant or pars flaccida of the eardrum to form retraction pocket and permanently infiltrate the external squamous epithelial layer of retraction pocket to excessively proliferate and keratinize, leading to formation of acquired cholesteatoma.</p>