Localized Cholesteatoma with Aerated Mastoid Cavity

Abstract

The aeration routes in 9 cases of localized cholesteatoma were evaluated by preoperativecomputed tomography and surgical findings. In 4 out of 5cases of attic type cholesteatoma, cholesteatomawas localized at the Prussak's space, and the tympanic isthmus was found to be patent.However, the anterior attic bony plate and associated mucosal folds completely separated the atticfrom the supratubal recess. In the remaining case the mastoid tip was aerated through a perforationof the matrix membrane of cholesteatoma. In 3 out of 4 cases of adhesive type cholesteatoma, cholesteatoma located within the vestibular window portion. Although both the anterior and theposterior tympanic isthmus were closed, an aeration route between the supratubal recess and theattic was found in all of these cases. A case with blocked anterior route showed a patency solelyof the posterior tympanic isthmus.
These cases. suggest that cholesteatoma can develop without complete blockage of so calledtympanic diaphragm. The significance of the anterior route as well as tympanic isthmus in the mastoidaeration was clarified.