主として胃粘膜下層に存在した胃癌の1例

A CASE OF GASTRIC CANCER MAINLY LOCALIZED IN THE SUBMUCOSAL LAYER

Ⅰ．まえがき

　胃癌は，通常胃粘膜固有層に原発し，胃表面より胃壁深部へ浸潤増殖するものである．

　一方，良性の上皮性elementが異所性に粘膜下層，時には筋層，漿膜下層に認められることがあるが，これが迷入膵組織であると確認できる場合も少なくない．かかる異所性の上皮を母地とする癌を想定する¹⁾²⁾³⁾ならば，胃粘膜固有層に癌組織の見られない胃癌もあり得るものと思われる．最近，私達は2個所の胃粘膜下層に，癌胞巣，をもった興味ある胃癌症例を経験したので報告する．

　A 61-year-old man was suspected prior to operation of harboring two Ⅱa type gastric cancer lesions in the antrum as well as multiple ulcers near the incisura. The gastric mucosa at operation revealed no apparent ulcer lesion on two indurations of a little-finger-tip size. Those indurations reddish in their mucosa were palpated on the lesser curvature and on the posterior wall in the pyloric region. Brushing cytologic examination was negative for cancer cells for the mucosa of the indurations. A frozen section from the induration on the pyloric lesser curvature revealed a gelatinous carcinoma.

　Histologicaly the resected stomach disclosed two cancer foci, the one located on the pyloric lesser curvature and the other on the posterior wall of the same region, each with a diameter of 2.0 cm. The cancer lesion on the lesser curvature, partly destroyed by foregoing histological examination, consisted of a gelatinous and solid carcinoma simplex, with a coverage of the submucosa and subserosa. The other lesion on the posterior wall, almost limited within the submucosa with a slight reverse infiltration from the submucosal layer to the basal part of the lamina propria, contained several kinds of cancer such as well differentiated tubular adenocarcinoma, acinar adenocarcinoma, gelatinous carcinoma and solid carcinoma simplex.

　No aberrant tissues were found around the focus on the posterior wall, but a tubulous structure similar to the pancreatic duct was observed in the deeper part of lamina propria directly above the cancer lesion. The tubule was neither connected with the cancer focus below nor with epithelial cells of the gastric mucosa nor with gastric pits.

　A possible cancer involvement from heterotopic tissues is suggested on the basis of the existence of a tubule similar to the pancreatic duct adjacent to the cancer focus, the presence of several kinds of cancer and localization of the cancer focus mostly the submucosal layer.