肉眼的に早期胃癌と判定した早期胃癌類似進行癌の実態―肉眼所見と組織学的所見

Characteristics of Advanced Gastric Cancer Macroscopically Mimicking Early Cancer

要旨　肉眼的に早期胃癌と判定した早期胃癌類似進行癌の実態を究明するために，胃癌手術例2,547例のうち，肉眼的に早期癌と診断した進行癌（以下表在型類進癌）59例を取り出し，年齢，性および組織型を一致させたsm癌とBorrmann型進行癌とを対比して，臨床病理学的に検索した．表在型類進はM領域に存在し，肉眼的にⅡc＋Ⅲ型を示す症例が多かった．深達度はBorrmann型に比べてpmが多く，脈管侵襲はsm癌と同等であり，リンパ節転移率，stageはsm癌に近い値を示した．組織学的に浸潤形式をみると，表在型類進癌は，潰瘍を伴いpm以下に微小浸潤を示す分化型癌の症例が多く，潰瘍を伴わない症例は，びまん浸潤を示す未分化型癌が多かったが，いずれの型も，pm以下に浸潤した癌の量は少なかった．また予後の面よりみると，5年生存率は，ss以下の癌が含まれているにもかかわらず，一般のpm癌よりよく，sm癌に近い値を示した．以上より，表在型類進癌は，早期癌と区別できないという肉眼的な所見をよく反映し，組織学的にもsm癌と近似の所見を示すpm以下に少量の癌細胞の浸潤を認める癌であった．したがって，早期癌から進行癌へ至る中間的な癌というより，むしろsm癌と同等の臨床的な評価を受けるべき癌と思われた．

　Fifty-nine cases of advanced gastric cancer macroscopically considered at early stage were studied for the presence or absence of microscopically characteristic findings. The lesion was macroscopically located in the middle portion of the stomach in 30 cases and classified as type Ⅱc or type Ⅱc+Ⅲ in 53 cases. Histologically, there was cancer invasion into the muscularis propria in 37 cases and ulcerated surface with a minute muscular or subserosal invasion in 28 cases. In other respects, clinico-pathologic findings were similar to those of early gastric carcinoma with submucosal invasion. Overall five-year survival rate was 85.2%, which was again as high as that for early gastric carcinoma with submucosal invasion.

　Those similarities of early gastric carcinoma with submucosal invasion and advanced carcinoma macroscopically considered at early stage, we assume, derive from the fact that there was minute cancer invasion into muscular layer as well as subserosal space. We thus feel that macroscopic classification is possible and useful without histological findings.