m3・sm1食道癌の病理

The Histopathological Examination of m3 and sm1 Early Esophageal Carcinomas

要旨　m₃癌18例，sm₁癌7例の計25例について病理組織学的検索を行い，深達度診断ならびにEMRの適応について検討した．肉眼所見はm_3-3より深い病変では小結節，癌巣の厚みが認められ，sm₁癌ではびらん・発赤による広範囲の粘膜表面の粗ぞうさが目立った．sm₁癌はm₃の領域が広く深達度が比較的推定しやすいものであったが，m₃癌は肉眼所見に乏しく，浸潤度の浅いものにはm₂癌との判別の難しい病変が少なくなかった．組織学的には，m₃癌は深達度m₁およびm₂の浅い部分が多くを占めて最深部の領域は狭く，最深部が粘膜筋板に深く浸潤するものも少なく，病変内で混在する癌巣の厚みの違いもわずかなものであった．m₃・sm₁癌はいずれも最深部分の占める割合は少なく，それらの深達度診断は最深部の深達度に基づいた肉眼像のとらえ方ではなく，深達度亜分類別の肉眼所見とその拡がりを十分に把握したうえで行わなければならないと言えた．更に，20mm以下の比較的小さな癌あるいは50mm以上の表層拡大型癌は診断が難しく，腫瘍径を考慮した診断学も必要である．一方，EMRの適応はリンパ管侵襲の有無からはm₂までを絶対適応としているが，リンパ節転移の可能性からm₃までを相対適応とした．しかし，症例数が少なく，今後の検討が必要と思われた．

　Eighteen cases of m₃ early esophageal carcinoma and seven cases of sm₁ carcinoma were examined histopathologically. This included macroscopical findings, mapping of the area of invasive depth of the carcinoma, degree of invasion to the muscularis mucosae, degree of dilatation of the muscularis mucosa, histological figures of carcinomatous epithelium and metastatic parameters. The macroscopic diagnosis of m₃ and sm₁ carcinomas and the indication for endoscopic mucosectomy of early esophageal carcinomas were discussed.

　The macroscopic diagnosis of invasive depth was more difficult in ms carcinoma. The accuracy rate was 33.3%. In contrast with this, the accuracy rate for sm₁ carcinoma was 70.1%. The reasons for misdiagnosis of m₃ carcinoma were fastly, the rate of m₃ invasive area was much smaller than that of m₁ and m₂. Secondly, the cases of carcinoma invading to the muscularis mucosae were relatively few. Thirdly, the dilatation of the muscularis mucosae and the focal thickness of the lesion, and the thickness of carcinomatous epithelium were not so different from one another and gradually shifted in each case. So to diagnosis m₃ early carcinomas exactly, the characteristic macroscopical findings, such as small nodules and small thickened area, should be detected over a wide area of slightly irregular mucosa. In addition, much more careful examination was needed in cases of small carcinoma less than 2 cm in diameter and large ones more than 5 cm in their largest diameter. To diagnose sm₁ carcinoma, spread of reddish and brownish irregular mucosa and thickening of mucosa over a wide area should be detected.

　The indication for endoscopic mucosectomy was not revealed in this study. From the date of metastatic tendency, intramucosal carcinomas invading to the muscularis mucosae are able to be resected endoscopically. However, after resection, detailed histopathological examination of all materials is necessary.