[Vascular degeneration in otosclerosis and its influence on the mesenchymal reaction of the mucoperiost].

38 samples of middle ear mucosa were taken from different patients during stapes surgery in otosclerosis. The samples were studied light-and electronmicroscopically without decalcification. Considerable pathologic changes in the organisation of the capillaries (endothelial hydrops, proliferation of the intima and of the adventitia, total obliteration o the vessels) cause pathologic reactions on the mesenchymal elements of the submucosa. Next to fibrolysis or hyalinosis of the collagen fibers the fibrocyts show features of undergoing lysis. Free and cellular bound calcium deposits are located in these lytic areas. The epithelial lining also shows unusual inclusions as glycogen and acid mucopolysaccharides and an alterated basement membrane. We belive that the changes of the connective tissue and of the epithelium are secundary to the capillary obstruction.