Mastoid pneumatization in children with congenital cholesteatoma: an aspect of the formation of open-type and closed-type cholesteatoma.

OBJECTIVES

To clarify mastoid pneumatization in children with congenital cholesteatoma and compare their clinical characteristics.

STUDY DESIGN

The mastoid pneumatization of 34 children with congenital middle ear cholesteatoma, of 34 age-matched children with unilateral acquired cholesteatoma, and of 17 age-matched control children without middle ear diseases was studied.

METHODS

The sizes of the mastoid cells were measured from 1.5-mm sliced semiaxial sections of a temporal bone computed tomography scan. The sum of the two areas from the two images, one showing the lateral semicircular canal and the other, 3 mm below this, was defined as the area of the pneumatized mastoid cells.

RESULTS

The mastoid cells in ears of children with congenital cholesteatoma were poorly pneumatized compared with those of control children without middle ear diseases, but were better pneumatized compared with those of children with acquired cholesteatoma. In children with congenital cholesteatoma, the degree of pneumatization in the cholesteatoma side was significantly poorer than that in the opposite side. A well-pneumatized mastoid was seen in ears with no episode of otitis media, in ears with the open-type cholesteatoma, and in ears with ossicular anomalies.

CONCLUSIONS

The presence of cholesteatoma matrix accelerates the inflammatory response when middle ear infections occur, and this probably leads to the suppression of mastoid pneumatization. The authors also propose the hypothesis that cholesteatoma in most congenital cases is the open type, and that middle ear inflammation may contribute to the formation of cystic and closed-type cholesteatoma.