単独Ⅱb6例の検討よりみたⅡb型早期胃癌の診断限界

Diagnostic Limitations of Type Ⅱb Early Gastric Cancer Experienced from Six Cases of Solitary Ⅱb Lesion

　Ⅱb型早期胃癌は“周辺正常粘膜と同じ高さを示す癌”と定義されているが，その解釈は各施設で必ずしも一定ではない．定義を厳しく解釈すれば臨床的にとらえうる症例はほとんどなくなり，逆に緩く解釈すれば比較的臨床的に診断の簡単なⅡaあるいはⅡc様病変まで類似Ⅱbとして報告されているのが現状である．今回，著者らは厳しい定義に基づく単独典型Ⅱbに近い病変6例を選び出し，そのX線，内視鏡および病理所見について検討を加え，本症の診断限界を考察したので報告する．

　Of 730 cases of early gastric cancer histologically examined in our laboratory, we have picked up six cases of solitary Ⅱb lesion, and the following results were obtained. In the definition of Ⅱb we selected, as a first step, those lesions whose margins were observed indistinctly in the fixed materials of the resected stomach, and there was no apparent difference in the “areae gastricae”between the lesion and the neighboring non-cancerous area. As a second step, we confirmed macroscopically hardly any difference in the height of mucosa as compared with the normal area in the cross sections of these lesions. Ⅱb was thus finally diagnosed and defined.

　1. Of six cases four were differentiated carcinomas, and the remaining two were undifferentiated. In differentiated type cancer was exposed in all cases over the surface of the mucosa. In three cases cancer was distributed in the entire part of the mucosal layer. In undifferentiated type the mucosal surface was covered with non-cancerous foveolar epithelium, and cancer was distributed only in the superficial part of the mucosal layer.

　2. Minute erosions were seen in one case out of four of differentiated type. In undifferentiated type erosions were seen in both cases.

　3. The size of cancer lesions measured from 1.3 to 5.5cm in diameter in differentiated type, while in undifferentiated type they were larger, measuring 6.0 to 8.5cm in diameter.

　4. Diagnosis of Ⅱb at the initial x-ray examination was made in one out of four cases in differentiated type. In undifferentiated type diagnosis was possible in both cases.

　5. X-ray findings differed according to the histologic type of cancer. Differentiated type was depitted as abnormal barium coating. Undifferentiated type. was visua: ized as fine granular appearance within abnormal barium coating.

　6. Endoscopic diagnosis was made in five out of six cases. In differentiated type cancerous part was observed as mucosal reddening without fine mucosal pattern. In undifferentiated type one out of two cases was seen as disappearance of fine mucosal pattern and pale discoloration. No noticeable abnormaliry was seen in the remaining one. Small bleeding spots were seen in one of differentiated type and also in one case of undi$erentiated type.

　7. The above results show that in differentiated type of early Ⅱb type gastric cancer a typical Ⅱb can be detected even when it be a very minute one. Undifferentiated type, on the other hand, could not be detected as a typical Ⅱb, but only as a Ⅱb-like cancer. For overcoming such diagnostic limitations, it would be necessary to develop x-ray apparatus with sharper focus and to introduce new endoscopic methods such as dye-scattering method and magnifying observation.