Ultrastructure of the mucus-negative vacuolated cells in the metaplastic pyloric gland of the human stomach.

Mucus-negative vacuolated cells, often with apical cilia, were found in the metaplastic pyloric gland of the human stomach. These vacuoles were not stained by various mucus stains, but contained neutral fat. Electron microscopic observation revealed that the ciliated cells had prominent autophagosomes in the supranuclear region and sometimes had large vacuoles. These vacuoles were limited by a unit membrane and had electron-lucent contents consisting of small amounts of lipid droplets and lamellar bodies. The non-mucus vacuolated cells might correspond to the mature ciliated cells in which cystic degeneration of the autophagosomes occurred after digestion by lysosomal enzymes.