HISTOGENETIC TYPES AND SIZE OF POLYPOID LESIONS IN THE STOMACH, WITH SPECIAL REFERENCE TO CANCEROUS CHANGE

Abstract

Histopathological study was made on 473 polypoid lesions in the stomach obtained surgically from 297 patients. The maximum diameter of each polypoid lesion was measured. Histological gradation based on the extent of the epithelial pseudostratification was used as the indicator of the process in the development of a polypoid lesion. Polypoid lesions were also classified histogenetically into the metaplastic and gastric types. The latter type was subdivided into the pure form and the mixed form with secondary metaplasia. The metaplastic type of polypoid lesions revealed a clear correlation between their size and histological grade, and showed a high incidence of cancerous lesions. Almost all polypoid lesions of this group had a diameter less than 20mm in the grades below V. Of the gastric type polypoids, on the other hand, the pure form not associated with intestinal metaplasia rarely underwent malignant change; and the average size of the lesions in each grade was larger than that of the metaplastic type. Approximately 10% of the pure form lesions in grades I, II, and III were found to have diameters larger than 20mm. The gastric type with secondary metaplasia revealed a combined character of both the metaplastic type and the pure gastric type in terms of the size as well as the malignant potential.