食道・胃境界領域の臨床胎生学および解剖学的検討

Clinico-embryological and -anatomical Study on the Metastatic Pathways of Cancer of Esophagocardiac Region

　癌の転移は，手術法の進歩，放射線療法や制癌剤の改良などをもってしても，なお治療の真正面にたちはだかる．ここでは食道・胃境界領域の癌の転移にかかわる経路について，臨床胎生学的，解剖学的観点からその要点の2，3をさぐりたい．

食道・胃境界領域の間膜の変容と所属リンパ節の帰属

　癌根治手術では癌巣の剔除，すなわち原発巣の除去と所属リンパ系統の廓清がなされる．リンパ系統廓清がとくにその核心をなすが，これをen blocに（過）不足なく徹底的に行わなければならない．ここでは，「リンパ節」といわずに「リンパ系統」の廓清と表現した．これは，リンパ節のみならず，それらをつなぐリンパ管，さらに組織内を四通八達する毛細リンパ管網などをen blocに除去しつくしたい意からである．

　From the viewpoints of clinical embryology and -anatomy, a study was performed on the lymphogenous and hematogenous matastatic pathways of cancers at esophago-cardiac region.

　1) Complete dissection of the regional lymph nodes at cancer operation usually assures good prognosis of the cases. In practice, however, the mesenteric structure of esophago-cardiac region is too intricate to determine draining lymph nodes and their grade. But in the early fetal stage, the mesenteric structure is so simple that it is rather easy to determine to which organs lymph nodes belong and their grade by the observation of distinct segmental appearance of various vessles running through the mesenterium. Light microscopic observation on the complete serial sections of human fetuses of various developmental stages, in addition to macroanatomic observation on the fetuses, enable us to know the developmental process that the dorsal mesogastrium transforms into gastropancreatic ligament by gradual shortening and broadening. With reference to this mesogastric transformation, the draining lymph nodes and their grade were determined in cases of esophago-cardiac cancer, and the anterior surface of renal fascia was removed as dorsal border of the dissection.

　2) In the esophago-cardiac area, there are collateral circulations from esophageal venous plexus to azygos (or hemiazygos) and to left lower pulmonary veins. Such collateral circulations are considered to be good candidates for hematogenous metastatic pathways, in addition to portal vein, in the cases of esophago-cardiac cancer.

　ⅰ. The former collateral circulation from esophageal venous plexus to azygos veins was clearly demonstrated in the venography of esophago-cardiac region of a rabbit.

　ⅱ. Distant metastases to organs were observed in 41 of 100 autopsy cases of gastric cancer, and 8 of 41 showed pulmonary metastasis but no hepatic one. No carcinomatous involvement of the mediastinum was evidence in two of 8, suggesting that the collateral circulations mentioned above were most possible hematogenous metastatic pathways in these two cases.