胆囊癌の発育・進展―肉眼型・壁内発育様式・癌の大きさからみて

Growth and Extention of Carcinoma of the Gallbladder

要旨　進行胆囊癌106病変を対象として胆囊壁内における癌の発育進展を検討した．粘膜面の高低からみた肉眼型は乳頭型12病変（11％），結節型34病変（32％），平坦（びまん浸潤）型24病変（23％），早期癌類似型36病変（33％）であった．106病変113浸潤病巣のうち，49病巣（43％）はびまん浸潤発育，33病巣（29％）は腫瘤浸潤発育，13病巣（12％）は腫瘤膨張発育を示し，残りの18病巣（16％）は漿膜下浸潤面積が0.5cm²以下の微小浸潤を示した．微小浸潤18病巣のうち5病巣（28％）はRokitansky-Aschoff洞（RAS）内癌からの漿膜下浸潤であった．各肉眼型の癌の大きさと深部発育様式や深部浸潤量との関係をみると，結節型癌は腫瘤形成発育を，平坦型癌はびまん浸潤発育を示し，共に粘膜内の癌の面積（m cm²）が15cm²以下であるとm≦ss（漿膜下の癌の面積）で，m＞15cm²であるとm＞ssであった。乳頭型癌でもm≒ss cm²とm＞ss cm²の2群が存在していた．早期癌類似型癌では癌の大きさと深部発育様式や深部浸潤量との間に相関はみられなかった．進行胆囊癌の発育進展の特徴として，漿膜下層のRAS内粘膜癌が直接漿膜下へ間質浸潤して進行癌になりうること，ある局面で粘膜から深部へ“すだれ”状にびまん浸潤すること，分化型癌であるにもかかわらず漿膜下層でリンパ管や組織間隙を通って側方へびまん浸潤すること，更に，胃癌と同じように“深部浸潤型癌”と“表層拡大型癌”に大別されることなどが挙げられよう．

　Characteristics of growth and extention of carcinoma of the gallbladder were histopathologically examined using 67 early carcinomas and 106 advanced carcinomas which had all been surgically resected.

　Macroscopic type, growth pattern and number of the carcinomas were shown in Table 2 and 3. Diffusely infiltrating growth pattern in the wall was most common in the advanced carcinomas even though they were well to moderately differentiated adenocarcinoma.

　The growth pattern was made up of multifocal direct invasion from the mucosa to the subserosa and of both lymphatic permeation and tissue-space spreading in the subserosa.

　Out of 18 foci of minute invasion, five (28％) indicated a microscopic stromal invasion of the subserosa through a Rokitansky-Aschoff sinus of the subserosa, and the remaining revealed continuous direct invasion to the subserosa from the mucosa.

　Advanced carcinoma of the gallbladder seems to be formed from early carcinoma by two different routes. Ratio of cancer-area in the mucosa to that in the subserosa was much different at the mucosal area of 15 cm² of both nodular carcinoma (Fig. 3) and flat carcinoma (Fig. 4). So both types of advanced carcinomas seem to be formed by two different routes; “deeply invading type or penetrating type” or “superficial spreading type or superficial type” of early carcinoma, which are common in gastric carcinomas.