ELECTRON MICROSCOPIC STUDIES OF THE POSTOPERATIVE MAXILLARY CYST

Abstract

Fine structure of the epithelia of the postoperative maxillary cysts has been studied under scanning and transmission electron microscope. Of 23 cases examined, 22 cases had the intact epithelial layer of different types.
The ciliated cells were present in 19 cases, but there were large variations in number. Based on the surface structures, we classified the epithelia into the following types.
Type I: densely ciliated surface with regular pattern of metachronal wave. (This type is very
close to the normal pseudostratified ciliated epithelium.)
Type II: epithelial surface with non-cilliated area of various extents.
Type IIa: no morphological changes in ciliary structures.
Type IIb: marked decrease in number of the cilliated cells with ultrastructural changes in the cillia.
Type III: complete absence of the ciliated cells in the surface.
Type IV: absence of regular surface structures occupied by various types of elliptical cells.
Metaplasia towards the squamous epithelium was observed in 3 cases. The goblet cells were increased in many cases. The fine structure of the mucosa of this disease was compared with those of the frontal mucocele and the chronic sinusitis. There were no obvious morphological differences among them.
Theories have been stated on the pathogenesis of this disease, discussed. The sinus obstruction theory seems most probable, although there are some cases not to be explained by this theory.