Histologic types and possible initial stages in early gastric carcinoma.

Among 2003 gastric specimens from 301 patients, diagnosis for carcinoma was made in 45 cases. Examination of resection preparations revealed 36 cases of deep invasive stomach carcinoma and 9 cases of early gastric cancer confined to mucosa and/or submucosa. Carcinomatous proliferations limited to mucosa or submucosa are classified in three histologic types: intestinal (adeno), mucocellular (signet ring cell), and anaplastic (solid) type of early gastric cancer. Mixed types have been found combining the first and the second, or the second and the third type. One case presented a mixture of all three types. Possible precursor or initial stages of all three types were found in further 31 biopsies. Some of them were glandular lesions in superficial parts of the mucosa; this kind has been described previously as possible preneoplastic stage of the intestinal type of early gastric cancer. "Signet ring cell drippings" from lower parts of tubule necks were recorded as an initial form of the signet ring cell type. The process is interpreted as detaching of isolated signet ring cells from a gland neck zone in progressing atypical transformation. An early neoplastic stage of the anaplastic (solid) type of early gastric cancer is identified in the "gland neck dysplasia" located exclusively in the antrum between surface mucosa and antrum glands. This lesion appears rich in cells and stretched like a broad ribbon. Early gastric cancer of this third type will arise in the very same location. Conclusions from formal histogenesis suggest that the signet ring cell type and the anaplastic (solid) type of early gastric cancer might start in the lower part of tubule necks. In consequence, the neck region of gastric glands could be the critical field of malignant transformation in the gastric mucosa. Long-term follow-up studies will be needed to verify these observations and their interpretation.