表在型食道癌肉眼分類の新しい提案―X線診断の立場から

A New Proposal of Macroscopic Classification of Superficial Esophageal Carcinoma

要旨　食道のep癌18病変，mm癌12病変，sm癌49病変を対象として，早期癌，および表在癌の定義，肉眼分類の妥当性を再検討した．その結果，“リンパ節転移の有無に関係なく，癌が上皮内，あるいは粘膜筋板までにとどまるもの”，すなわち，ep癌・mm癌のみを早期癌と定義することを提唱した．このように定義された病変の肉眼所見は胃の早期癌肉眼分類の4つの基本型で分類可能であることを述べた。次に，ep癌・mm癌の肉眼所見の特徴を，隆起性病変は“顆粒”の要素，陥凹性病変は“面”，“溝”の2つの要素から成ることを明らかにした．最後に，ep癌・mm癌の固定標本のルゴール塗布像，術後・術前の二重造影像を対比し，肉眼所見とX線所見の写像の対応の問題を論じ，初回検査でもep癌・mm癌を発見できる可能性があることを強調した．

　The diagnostic possibility of early or superficial esophageal carcinoma in the initial (routine) radiographic examination was assessed by reevaluation of their gross findings, based on 79 lesions (ep-ca: 18, mm-ca: 12 and sm-ca: 49 lesions) which had been experienced between 1972 and 1986 at The Dept. of Gastroenterology, Juntendo University, and The Cancer Institute Hospital.

　Early carcinoma of the esophagus is defined as carcinoma which is limited to the submucosa without lymph node metastasis, and superficial carcinoma is defined as that which is limited to the submucosa with lymph node metastasis. Carcinoma confined to the epithelium is called ep-carcinoma (ep-ca), that limited to the muscularis mucosae is called mm-carcinoma (mm-ca), and that involving the submucosa is called sm-carcinoma (sm-ca) (Japanese Society of Esophageal Diseases). These two types of carcinoma with the same depth of invasion (early and superficial) are inconveniently used in the clinical diagnoses.

　In considering such an incovenience in the clinical diagnosis of the present definition and unfavorable prognosis of sm-ca, a new definition of early carcinoma which refers to that which is limited to the epithelium (ep-ca) or muscularis mucosae (mm-ca) was proposed, excluding sm-ca. The gross findings of early carcinomas newly defined could be classified into four basic types of early gastric cancer (Type Ⅰ, Ⅱa, Ⅱb and Ⅱc).

　Granularity was characteristic of ep- and mm-ca in polypoid type (Type Ⅰ) and superficial elevated type (Type Ⅱa). The gross findings of superficial depressed type (Ⅱc) was divided into two types which were characteristic of ep- and mm-ca ; the one consisting of irregular surface depression and the other consisting of irregular grooves.

　These characteristics of gross findings of Ⅱc-lesion were seen most prominently on the Lugol sprayed specimen after fixation, and were precisely reproduced on the postoperative double contrast radiographs. However, the preoperative double contrast radiographs were not able to delineate them satisfactorily though the corresponding points between pre- and postoperative double contrast radiographs were indicated in most cases when they came to a frontal view. In ep-ca the minimum degree of poor distensibility and irregularity of the margin were visualized on a profile view in slight esophageal distension. These marginal abnormalities were effaced in moderate esophageal distension while they were not effaced by changing degree of esophageal distension in mm-ca. It was suggested that ep- and mm-ca could be detected in the initial radiographic examination through meticulous interpretation.