胃びまん性癌における粘膜内癌浸潤と線維化についての病理学的考察

Pathological Study of Diffuse Infiltrative Carcinoma of Stomach

　わが国では臨床的にスキルスと呼ばれているものとBorrmann 4型胃癌は同じものと解釈されている．しかし病理学的にはスキルス，Borrmann 4型癌，びまん性癌，linitis plastica等といわれているものは各研究者によりその定義は多少異なっている．現在はこれらの名称がいずれも使われ，スキルスの定義をめぐり混乱を来している状態である．欧文の文献にみられるlinitis plastica，びまん性癌，Borrmann 4型癌はいずれも高度の膠原線維の増生を伴い，胃壁全体が平板状に硬化し，leather bottleとも呼ばれる外見を呈するもので，わが国で臨床的に呼ばれてきたスキルスに相当する．

　著者らは今までこのような癌は予後の最も悪いもので，大部分は3年以内に死亡し，臨床的，病理学的に通常の胃癌とは生物学的に異なった性格を有する特殊な癌であることを主張してきた．すなわち，Borrmann 4型癌は臨床的には一見非常に経過が早く，また病理学的には単に表層拡大型胃癌の末期像ではなく，特殊な進展形式を示し，かつ胃全体に高度の線維増生を来す癌であることを，臨床経過追跡資料および外科的手術材料よりその究明に努めてきた．これらについては今まで多くの発表をしてきたので，今回はびまん性癌の肉眼像および高度の線維増生（fibrosis）の成因について病理学的な著者らの考えを述べる．

　Borrmann's type 4 carcinoma corresponds to diffusely infiltrative carcinoma or linitis plastica. This type of carcinoma manifests diffusely extensive infiltration of tumor cells along the gastric wall, and show marked thickning and stiffning of the gastric wall by remarkable fibrosis. Diffuse carcinoma constitutes about 10％ of whole gastric carcinoma, and the prognosis is very poor which three year survival rate is nearly 0％.

　Many clinical doctors have experienced remarkable change－ex. contraction of the gastric wall－of this type of carcinoma following 1 to 2 years. Therefore we think that diffuse carcinoma is one special type of carcinoma having different biological characters compared with the other gastric carcinoma. And diffuse carcinoma is not terminal stage of the superficial spreading carcinoma.

　There are three stages diffuse infiltrative carcinoma following－

　1. Infiltrative stage: cancer cells widely extensive by lymphatic channels.

　2. Edematous stage: soluble collagen appears in gastric wall in this stage.

　3. Sclerosing stage: soluble collagen changes to insoluble collagen and then gastric wall displays marked thickning and stiffness. This is end stage of the diffuse carcinoma of the stomach.

　It is difficult to explain that marked fibrosis of gastric wall is stromal reaction by tumor cells infiltration, because of more extensively fibrosis of gastric wall and clinically gastric wall changes to stiffness in very short time.

　Probably production of much soluble collagen is closely relationship to cancer cells. Metastatic carcinoma of the rectum and colon, originated from gastric diffuse carcinoma, show linitis plastica, and breast carcinoma metastases to stomach and colon where show linitis plastica. The other hand, it is known that breast carcinoma cells produced chondroitin-sulphate as stroma of cartilage. From these facts, we suggest that tumor cells of diffuse carcinoma of the stomach possibly produce collagen.