Search

On the basis of analysis of the histological structure of 1,095 polypoid and nonpolypoid tumors, the frequency of detection of "primary" carcinoma and its clinical and histological features were studied. It is shown that one third of pTI category carcinomas are devoid of signs of a preceding adenoma. Polypoid primary carcinomas account for only 15.8% of cases. The prevailing plaque-like, flat, and ulcerated tumors invade the submucous layer more frequently than malignancy adenomas of the corresponding size and produce metastases to the lymph nodes more frequently. The tumor develops against the background of precancerous and dysplastic changes in the epithelium in the nonpolypoid mucosa and in the adenomas. The indications for economical operations in primary carcinoma, in distinct from those in malignancy adenomas, should be determined with caution.

A study on alterations occurring in gastric mucosa in cases of stage I stomach cancer identified chronic gastritis involving gland atrophy of varying degree as the basic background feature, with intestinal metaplasia and dysplasia being common manifestations of precancerous lesion development. Malignant transformation of hyperplastic polyps and adenomas occurs in areas in which dysplasia of metaplastic epithelium tends to spread. Stomach cancer development from gastric ulcer seems unlikely. Morphological factors should be considered, when groups of high risk for stomach cancer development are identified among cases of chronic gastric diseases.