Ultrastruct of oral cells with bar-shaped nuclear chromatin.

Scrapings were taken from the frenulum of the lower lip to obtain cells with bar-shaped nuclear chromatin. They were subjected to routine electron microscope processing, sectioning and visualization. Specimens from the lower frenulum of autopsy patients were prepared for light microscope identification of the bar-chromatin cell in tissue. The ultrastructure of the bar-chromatin cell cytoplasm resembled that of normal squamous intermediate cells, but the nuclear chromatin was composed of pleomorphic masses which formed an irregular band on the long axis of the nucleus. In the normal intermediate cell the clumps of chromatin were dispersed randomly. Cells with bar chromatin were found in the stratum spinosum of the oral squamous epithelium.