Cytoplasmic granules in exfoliated buccal epithelial cells.

The cytoplasmic granules in exfoliated epithelial cells of healthy cheek mucosae of seven subjects were studied by means of phase-contrast microscopy, electron microscopy and histochemistry. An electron microscopic technique was used to study specific granules which had been identified with the light microscope. Phase-contrast microscopy revealed that the cytoplasmic granules are present in unfixed material. Ultrastructurally they consist mostly of discrete, dense granular bodies. Also seen were collections of electron-dense masses, collections of organelles and organelles mixed with granular bodies and electron-dense masses. Histochemically they stain like keratohyalin. No lipids were detected. We propose that the discrete bodies are normal keratohyalin granules and the electron-dense masses are granules in stages of disintegration. When the granules break down they become mixed with organelles. The keratohyalin granules are the darkly-stained granules seen microscopically, and the disintegrating granules and collections of organelles the weakly-stained, indistinct cytoplasmic granules.