Early Endoscopic Findings in Follow-up Cases of Small Gastric Cancer; The Difference between Differentiated and Undifferentiated Types Shigeaki Yoshida 1 , Atsushi Ohtsu 1 , Hajime Yamaguchi 1 , Mitsuya Yoshino 1 , Teruyuki Hirota 2 1Department of Internal Medicine, National Cancer Center Hospital 2Division of Pathology, National Cancer Center Research Institute pp.1379-1386
Published Date 1989/12/25
DOI https://doi.org/10.11477/mf.1403106639
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 The proportion of undifferentiated (untubular) type of gastric cancer is quite small among minute lesions. In order to clarify the diagnostic difficulty in detecting small gastric cancers of undifferentiated type, endoscopic findings in follow-up cases of gastric cancer smaller than 2 cm in diameter were examined retrospectively. During the period between 1970 and 1987,101 cases of gastric cancer were followed-up because it was undetermined whether the lesion was malignant or not at the previous examination performed within five years prior to the latest examination. Of the 101 cases 36 measured less than 2 cm on the resected specimen and were selected as the subjects of this study. The endoscopic findings observed at the previous examination (early endoscopic findings) in the 36 cases were grossly classified into the following four categories; 1) no abnormality detected (N.A.D.). 2) small discolored,3) erosive and 4) ulcerative lesions.

 Of the 36 cases 17 were undifferentiated and 19 differentiated (tubular) types of adenocarcinoma histologically. Among early endoscopic findings of the former type, category of N.A.D. was the most frequent (41%) and included two cases of Ⅱb (flat) type early gastric cancer measuring 1.5 and 2 cm, respectively. In these cases detecting abnormality was quite difficult even on the endoscopic pictures taken at the latest examination. Among other cases in this category, significantly large cancer lesions seemed to develop suddenly from no abnormal mucosa as seen in Case 1 (Figs.1 and 2), except for a case of minute cancer sized 6 mm.

 In contrast, among early endoscopic findings of the 19 cases of differentiated type, category of ulcerative lesion was the most frequent (47%), followed by that of erosive one (32%). In the 15 cases classified into these two categories detecting mucosal abnormality was easily done retrospectively as shown in Case 4. In 7 (47%) of these 15 cases, malignant nature of the lesion was suspected even on the endoscopic pictures taken at the previous examination. The remaining 4 of the 19 cases of differentiated type were classified into category of N.A.D., and 3 of these 4 cases had a minute cancer sized less than 5 mm.

 The category of small discolored lesion as shown in Case 2 included only 3 cases and was the least frequent among the 4. All 3 cases, however, fell into undifferentiated type, and one (Case 3) of the 3 cases developed conventional Ⅱc from N.A.D. through small discoloration during the prospective follow-up period, indicating that the small discoloration is characteristic to undifferentiated type of gastric cancer, as reported in the previous literatures.

 The above results suggest that detecting undifferentiated type small gastric cancer is much more difficult than that for differentiated one. In order to detect small undifferentiated type gastric cancer, cautious observation for small discoloration or biopsy from benignlooking or erosive lesion is indispensable.

Copyright © 1989, Igaku-Shoin Ltd. All rights reserved.


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