表層拡大型胃癌の病理

Pathology of Superficial Spreading Type of Gastric Cancer

　表層拡大型（表拡型）というのはA. P. Stout²⁾のsuperficial spreading typeの訳である．

　Stoutの“superficial spreading type of carcinoma of the stomach”Ach. of Surg. 1942によると，彼の経験した69例の切除胃癌のうち15例22％にsuperficial spreading type of carcinoma（表拡型胃癌）と称すべき表在性に拡がる傾向の強い癌を発見したと述べている．そしてその深達度は1例のみがいわゆる粘膜癌で，その他はすべて粘膜下層または固有筋層まで癌の浸潤が達していたという．他方，癌の拡がりの面積については，深達度の浅い割りに広いということを取り上げているだけで，正確な広さについては触れていない．

　Superficial spreading type of gastric cancer as designated by A. P. Stout is characterized by (1) wide superficial spread of cancer in comparison with shallowness of vertical invasion; (2) the greatest majority of carcinoma solidum simplex mucocellulare; and its far better postoperative prognosis as compared with other types of gastric cancer. No definition was ever made as to the extent of cancer spread.

　With this fact in mind, we have collected cases of early gastric cancer whose horizontal spread was remarkable in contrast with minor vertical involvement. Those whose longest diameters by the diameters perpendicular to them were more than 25 are called superficial spreading type in a wider sense of the words, while lesions that have cancer cells of mucocellular type are called superficial spreading type in a narrower sense.

　The results of our examinations show that it is hardly possible to substantiate the existence of superficial spreading behavior of cancer evolution anticipated and defined by Stout. Furthermore, the histologic type of this variety of cancer is not limited to mucocellular type; tubular variety is not infrequent. Consequently, the mode of cancer spread should not be looked for merely in the horizontal direction but multicentral genesis of cancer must by all means be taken into account. Surgeons are especially cautioned about the determination of the area to be resected in superficial spreading type having a great extent.