Histopathological study of otitis media with effusion.

Thirteen temporal bones with otitis media with effusion (OME) taken from ten patients were studied. The effusions in the tympanum were histologically classifed into serous and mucoid types. In the serous effusion, neutrophils were dominantly distributed and the mucosa and submucosa showed inflammatory signs. Few epithelial cells and lymphocytes were observed in the effusion of the mucoid type. Eosinophils were rarely seen in the effusions of both types. The presence of inflammatory process was a common finding in OME, particularly with serous effusion. A case, with an immunologic disorder suspected, showed an extensive proliferation of mucosa and unusually thick liquid in the middle ear. This histological feature of the case did not resemble those of other ears with mucoid type of effusion.