Mast cells of the human stomach.

Mast cells were examined from various sites in the normal human stomach and in the stomachs of patients with gastric ulceration. The distribution of the different types of mast cell granules was determined in the subepithelial region of the normal human stomach. There was a significant difference in this respect between the mast cells at the incisura angularis as compared with those high on the lesser curve or high on the greater curve. Mast cell degranulation (i.e. the shedding of intact granules) and vacuolation were examined with the electron microscope. Degranulation and vacuolation were observed in subepithelial mast cells, whereas only vacuolation was seen in intraepithelial mast cells. The significance of degranulation and vacuolation is discussed.