Abstract

The author studied 11-cases of adenocarcinoma of the stomach confirmed by gastrofiberscopic biopsy before in order to differentiate between differentiated and undifferentiated adenocarcinoma by scanning electron microscope. Light and transmission electron microscopie examination were done, too. Seven of them are differentiated accompanied by severe intestinal metaplasia and four of them are undifferentiated with rearly focal intestinal metaplasia. Two of the undifferentiated cases shows focal tubular differentiation on the superficial region of the mucosa. Microvilli on the free border are long, regular on the differentiated type but in state of variable loss of microvilli under the transmission electron microscope. Number and density of the mucous granules are variable. Scanning electron microscopic examination shows prominent disorganization of the folds, cellular pleomorphism and pleomorphic microvilli are suggestive of early marker of neoplastic transformation. The size of them are 0.6 micrometer and 1.2 micrometer on the differentiated type respectively. Disorganization of the folds is an important differential point between differentiated and undifferentiated type on the lower power examination. Development of folds, furrow, and hemispheric colliculi are more porminent on the differentiated adenocarcinoma. Presence of striated border, partial or complete loss of microvilli and intestinal metaplasia on the undifferentiated and differentiated adenocarcinomas are consisent with origin from common precursor cells.