Abstract
Histologically gastric cancers are classified into two major categories, differentiated and undifferentiated types. In the latter, most of the lesions are combined by the ulcerative change within cancerous area (ulcerative cancer) histologically. The endoscopic detection of these cancers is usually easy, because of the macroscopic appearances of ulcerative changes, although they may originate from the non-ulcerative lesions, theoretically, . So, we attempted to clarify whether non-ulcerative cancers of undifferentiated type to be consid-ered as earlier than the ulcerative, or the two types to be considered as originally different each other in the selected cases of similar endoscopic findings (excluding diagnostic bias). During the period between 1962 and 1985, 1, 242 cases of solitary early gastric cancer had been operated at the National Cancer Center Hospital. Of the 1, 242, 71 cases of undifferentiated type were considered to be superficial and nonulcerative, endoscopically, and were analyzed for this study. Of the 71 cases, 51 were ulcerative and the rest 20 non -ulcerative, histologically, in spite of their similar endoscopic appearances. A comparative study was performed between these ulcerative and non-ulcerative cancers, endoscopically and clinicopathologically. The results were as follows : 1) In the non-ulcerative groupe, older and male patients were more dominant than in the ulcerative. And, there was no significant differences (between ulcerative and non-ulcerative cancers) in size, site and vertical invasion of the lesion. 2) In the non-ulcerative groupe, poorly differentiated adenocarcinoma was more dominant than signet ring cell carcinoma histologically, though in the ulcerative groupe. signet ring cell type was dominant (P <0.05) 3) Endoscopically, discoloration was frequently obserebed in the non-ulcerative groupe (60%), while in ulcerative groupe less frequent (37%). 4) Incidence of the cases with less malignant endoscopic appearences was almost the same between ulcerative and non-ulcerative groupe. In conclusion, the above results may suggest that a early gastric cancer of undiffer-entiated type has a tendency to ulcerate within cancerous area at the very early stage. And we concider that non-ulcerative cancers studied at present do'nt develop from the common source of ulcerative cancers.
