Ultrastructural morphometry and secretory behavior of acinic cell carcinoma

Cells from three parotid acinic cell carcinomas were compared stereologically with normal parotid acinar cells. The morphometric studies revealed that the granular volume density was increased in the tumor cells. The cells contained more granules, but the mean granule diameter was considerably less, compared with normal controls. On the other hand, no difference in cell volume or nuclear volume density could be found. Although morphologically similar to normal acinar cells, the tumor cells had a much lower content of amylase. However, in a batch-incubated system, amylase secretion could be elicited with noradrenaline from the tumor cells. Furthermore, noradrenaline stimulation increases tumor tissue cyclic AMP content dramatically. The current study demonstrated the similarity between normal acinar cells and acinic cell tumor cells: the latter respond to physiologic secretion stimuli with an increased tissue level of cyclic AMP accompanied by amylase release.