Scanning and Transmission Electron Microscopic Study of Odontogenic Cysts

Forty-three cases of odontogenic cysts (20 radicular cysts, 20 follicular cysts, and 3 calcifying odontogenic cysts) developing in the human maxillo-oral region were examined by scanning and transmission electron microscope. The results were as follows : 1. Radicular cysts Connective tissue : The connective tissue consisted of mature collagen fibers running in a comparatively systematic formation. However, their arrangement was coarse. Infiltration of inflammatory cells and dilation of capillary endothelia were remarkable. Squamous epithelium layer : In all cases, stratified epithelium of three to seven layers were observed but no keratinized layers were seen. Many vacuolar structures were recognized in the superficial cytoplasm. Desmosome was few and the space was wide in the connective form. 2. Follicular cysts Connective tissue : Mature collagen fibers increased densely, meander patterns, and crossed among the elongated cytoplasmic proccsess of fibroblasts. The infiltration of inflammatory cells were remarkable in part. Squamous epithelium layer : The cyst wall consisted of five to ten or more layers. These arrangements were comparatively dense and regular. Connections were made mostly by the interdigitation and desmosome. The density decreased suddenly from the stratum spinosum to the outmost superficial layer. 3. Calcifying odontogenic cysts Connective tissue : Mature collagen fibers clearly increased and ran in meander and spiral patterns. Among these fibers, many degenerative cells derived from mesenchyma consisting of blood cells for the most part were observed. Squamous epithelium layer : The epithelial cells consisting of five to ten or more layers showed an irregular arrangement. The ghost cell forms showed appearances of onion, and but patterns. The fine fibers radiated in the ghost cell's cytoplasm. In the ghost cell's cytoplasm, a mesh-structure consisting of a thin membrane covering the mesh and fine fibers, and granular deposition on the membrane and fine fibers were observed. In transmission electron microscope, the development of ghost cell's organelles was poor and the ghost cell was filled with tonofilament bundles. The intercellular connective form appeared close, and tonofilament and keratohyaline granules were seen in the cytoplasm of horny layers. Appearance of calcification was recognized remarkably in part.