大腸villous tumor50例の臨床病理学的検討

Characteristics of Villous Tumors of the Large Intestine: Clinicopathologic Study of Fifty Cases

要旨　大腸のvillous tumor手術例（腺腫11例，早期癌13例，進行癌26例を含む）50例を対象として，それらの肉眼的特徴，villous adenomaの癌化率を検討した．villous tumorの81.8～88.5％は絨毛状～乳頭状突起の集簇より成る表面性状を持っており，肉眼的に診断しえた．癌病巣のうち，塊状に粘膜下層に浸潤した早期癌と進行癌は潰瘍，陥凹，小区の癒合，破壊像のいずれかの肉眼所見を示し，100％癌の肉眼診断は可能であった．粘膜内癌のうち，上記所見を示したものを除く78％の癌は肉眼的に診断できなかった．進行villous carcinomaでも，癌辺縁粘膜隆起が正常粘膜から成るもの（粘膜下層に塊状に癌が浸潤している所見で，進行癌を疑わせる）は15/26例（57.7％）にすぎず，残りの42.3％は早期癌との鑑別が困難であった．villous adenomaの癌化率は，高異型（high grade atypia）の部分を腺腫とすると73.8％，癌とすると72.7％であり，組織異型度の基準の差を考慮しても差はなかった．

　Fifty cases of villous tumor of the large intestine, resected surgically, were examined on the macroscopic characteristics and the incidence of malignant trans-formation. The case material included 11 patients with adenoma, 13 with early cancers and 26 with advanced cancers.

　Macroscopically, it was not difficult to diagnose villous tumors because most (86%) of such cases had papillary surface appearance. All cases of either advanced cancer or early cancer with submucosal invasion were correctly daignosed based on such findings as ulceration, erosion, depression, and destructed mucosal area pattern.

　On the other hand, these visible abnormalities were not observed in 78% of intramucosal cancer cases, which made its diagnosis difficult. Thirty-eight cases also lacked typical macroscopic findings of massive invasion into the submucosa, i.e., the surrounding non-neoplastic mucosa being pushed upwards. Again in such cases was it difficult to differentiate them from early cancer.

　The proportion of malignancy transformation in the villous adenoma was 73.8% when high grade atypia was considered as adenoma, but it decreases to 72.3% when high grade atypia was considered as cancer. The difference between these two proportions was, we thought not significant.