Aspects of the fine anatomy of aphthous stomatitis.

Samples of human aphthous stomatitis were studied under the electron microscope. The epithelial cells bordering the ulcer present multivesicular bodies, pinocytotic vesicles, primary lysosomes, digestive vacuoles, and autophagic vacuoles. The golgicomplex is noticeably increased; free ribosomes and rough endoplasmic reticulum are abundant. Crystalline structures are close to the nucleus. One or two paranuclear bodies are in most of the nuclei. A frank cell injury is evident, causing a major activity of the digestive cell system; the origin and formation of lysosomes through r.e.r. and the Golgi system are discussed.