[Localization of inflammation of tympanic cavity in human temporal bone pathology]

When we treat patients of otitis media, it is important to know the pathogenesis of otitis media. Therefore histopathological change of epithelium and bone in each site of tympanic cavity was observed using human temporal bones. Histopathological change of epithelium was classified as: acute, subacute and chronic in eighteen sites of tympanic cavity. Histopathological change of bone was observed in thirteen sites of tympanic cavity. And the frequency of histopathological change of epithelium and bone in each site was compared. A review of 350 temporal bones collected from autopsy cases revealed 171 (49.1%) to have otitis media, and a review of 170 temporal bones of otitis media cases revealed 165 (97.1%) to have bone changes. Differences in frequency of histopathological change of epithelium and bone existed in each site. Histopathological change in inferior portion of mastoid cells, round window niche and tympanic sinus was more frequent than in the other sites. Change of epithelium: in acute inflammation, no differences in frequency of histopathological change existed; in subacute inflammation and chronic inflammation, differences in frequency of histopathological change existed in each site. Change of bone: most changes were bone formation and bone reconstruction, but there was no clear finding that bone formation narrowed tympanic cavity without mastoid cells. Osseous destruction was found in mastoidectomy cases and cholesteatoma cases. It is thought that the frequency of inflammation is related to structure of cavity, aeration, immunologic activity or structure of the epithelium, and that the pathogenesis of otitis media, especially in chronic otitis media, is different in each site of tympanic cavity. It is thought that because the subjects of this study were not operated cases but autopsy cases, slight bone change was very frequent, but severe bone change, was rare. And we examined the pathogenesis of tympanic cavity of each case of acute inflammation and chronic inflammation of pars tensa and cases where there were no findings of inflammation in the pars tensa. In most cases of acute inflammation of pars tensa, inflammation of tympanic cavity was acute; in chronic inflammation of pars tensa, chronic. It was interesting that, in cases of normal pars tensa, inflammation was frequently found in tympanic cavity. Therefore, it is important to pay attention to the possibility of inflammation in tympanic cavity, even if the tympanic membrane appears normal.