m3・sm1食道扁平上皮癌の病理

Histopathology of m3 and sm1 Invasive Squamous Cell Carcinoma of the Esophagus with Special Reference to Endoscopic Resection

要旨　食道扁平上皮癌のうちm₃癌16例とsm₁癌17例を用いて，どのような病理形態学的特徴を持つm₃・sm₁癌がEMR治療の対象となりうるか(外科的追加切除が不要か)を検討した．m₃癌はリンパ節転移陰性であったが，2例でly(＋)/v(＋)がみられた．これらはすべて粘膜筋板に浸潤した癌であった．現在のm₃癌は粘膜筋板に接するm₃癌と粘膜筋板に浸潤したmm癌とに区別する必要があろう．相対値で表現されるsm₁癌はEMR治療が完全か否かの判定に有用ではない．実測値のsm浸潤長がO.20mm以下で，ly(－)/v(－)のsm癌のみがEMR治療完治例と判定されうることが示唆された．

　Endoscopic mucosal resection (EMR) of m₁ (intraepithelial ＝ in situ) and m₂ (invading the lower half of the lamina propria, but not attached to or invading the muscularis mucosae) carcinoma of the esophagus is common in Japan. However, some of carcinomas treated by EMR show invasion down to or into the muscularis mucosae (this type is called m₃ carcinoma in Japan), or the upper third of the submucosa (sm₁ carcinoma). There is no definite answer as to whether these carcinomas found in EMR specimens should be treated with additional surgical resection including lymph nodes. The aim of this paper is to make clear which m₃ or sm₁ carcinomas are free of lymph node metastasis, and treatable with EMR only, without resorting to surgery.

　We used 16 m₃ and 17 sm₁ carcinomas which were selected from our file. m₃ cancer did not show lymph node metastasis, but two of the 16 revealed lymphatic or venous invasion. These two were only cases invading into the muscularis mucosae (seven carcinomas; invading into the muscularis mucosae, and nine invading down as far as it).

　Two of the 17 sm₁ carcinomas showed lymph node metastasis. In these two, the length of submucosal invasion vertical to the muscularis mucosae was 0.21 and 0.24 mm. Eleven sm₁ carcinomas with 0.03 to 0.20 mm submucosal invasion were negative for nodal metastasis, but four of them were positive for lymphatic/venous invasion.

　The nodal metastasis showed a statistically significant correlation to lymphatiac/venous invasion as well as to high-grade atypia of carcinoma cells.

　From these data, it could be suggested that the present m₃ carcinoma should be divided into m₃ carcinomas invading down to the muscularis mucosae and mm carcinoma invading into it, and that EMR treatment is sufficient in cases of m₃ carcinoma (by the new classification) and mm carcinoma without lymphatic/venous invasion and in cases of sm₁ carcinoma invading down to 0.20 mm in vertical length without lymphatic/venous invasion.