Figure 6. Structure of apical true cysts (a,b). The cyst lumina (LU) are completely enclosed in stratified squamous epithelium (EP). Note the absence of any communication of the cyst lumen with the root canal (RC in b). The demarcated area in a is magnified in c. Arrowheads in c indicate cholesterol clefts. Magnifications; (a) 30x, (b) 17x, and (c) 60x. (From Nair et al., 1996.)