粘膜下腫瘍様の形態を示す胃癌―病理学的検討

Characteristic Feature of the Gastric Carcinoma with Submucosal Tumor Like Appearance

要旨　粘膜下腫瘍様の形態を示す胃癌(SMT様癌)の特徴を知るために，22例のSMT様癌，5例のcarcinoid tumor，10例の粘膜下腫瘍(SMT)を検討した．SMT様腫瘍の組織型は，リンパ球浸潤癌9例，充実性に増殖する癌が4例，限局線維化を伴う癌が6例，粘液癌が1例，内分泌癌が1例，分化型癌が1例であった．SMT様癌は，従来報告が多い組織型に加えて，線維化の強い限局したscirrhous carcinomaの症例が相当数含まれていた．また，SMT様癌は，進行しても，腫瘍の立ち上がりの角度は減少するが，その他の形態の比は保たれていた．SMT様癌は，carcinoidとの比較で，大きさに比べて陥凹の面積が大きく，深く，逆に，高さおよび腫瘍の立ち上がりの角度は小さいという結果であった．SMT様癌は，SMTとの比較では，腫瘍の大きさに比較して，陥凹面が広く，陥凹周辺にIIcあるいはIIc様の変化を見出すことが重要であった．

　Gastric cancer with submucosal tumor-like appearance (SMT-like carcinoma) is hard to diagnose if we rely only on its macroscopic features. We examined twenty-two SMT-like carcinomas, 5 carcinoid tumors (carcinoid) and 10 mesenchymal tumors (SMT) to clarify their microscopic and histological characteristic features.

　The histological type of SMT-like carcinomas was verified in 9 cases of medullary carcinoma with lymphoid stroma, in 4 cases of carcinomas with solid growth, in 6 cases of localized carcinoma with severe fibrosis, in 1 case of mucinous adenocarcinoma, in 1 case of endocrine cell carcinoma and in 1 case of differentiated carcinoma.

　It was noted that localized carcinoma with severe fibrosis was one of the most predominate types.

　SMT-type carcinoma developed while preserving almost all of its macroscopic proportion, but the building up angle of the tumor gradually decreased.

　In comparison with carcinoid tumor, SMT-like carcinoma showed a higher rate of wide concavity, a higher rate of deep concavity, a lower height and a lower building up angle than that of carcinoid tumors.

　SMT-like carcinomas showed a higher prevalence of wide concavity than SMT, and also showed a IIc region at the periphery of the concavity in most cases.