Electron microscopic study of signet-ring cells in diffuse carcinoma of the human stomach.

The signet-ring cells seen in gastric carcinoma of the diffuse type were studied by light and electron microscopy. A classification of these cells into Types A, B and C was developed, based on intracellular mucous granules, nuclei and organelles, and be reactions to PAS and Alcian-blue staining. The gradual transition of type A cells to Type B and the subsequent change of Type B to Type C suggest successive stages in maturation. These cells, especially those of Type B, resemble the mucous neck cells of the corpus and the glands of the pylorus.