大腸villous tumorの問題点

Villous Tumor of the Colon

要旨　大腸villous tumorは肉眼的ならびに組織学的に顕著な絨毛状あるいは乳頭状増殖を示すことより命名された．連続切片による再構築ではその構造はfoliaと言われるものである．villous tumorでは核分裂像は乳頭状構造の基底部から先端部まで認められ，増殖帯が広く分布し，表層に増殖帯の存在する管状腺腫とは異なる．その増殖はもっぱら垂直方向であり，特殊な狭い問質を誘導し乳頭状形態を呈する．上皮は種々の程度の異型を示し，異型の強いものは高分化腺癌と考えられる．villous tumorの癌化に関しては，まずその本態を究明することが肝要であり，細胞動態あるいは組織計測などを用いて管状腺腫や高分化腺癌との客観的な比較検討を要する．

　Villous and papillary patterns, both macroscopically and microscopically, are most characteristic findings of villous tumor. Although precise morphogenesis of villous tumor is unknown, the mitotic activity ubiquitously seen in the neoplastic papilla, from the base to the tip, indicates the widely distributed growth zones in the tumor. The epithelia show vertical growth at the margin of the tumor partly replacing the original crypts. The degree of epithelial atypia varies from case to case, and from place to place even in a single tumor. At least, ones which are composed of epithelia with the most severe atypia should be regarded as carcinoma. To evaluate the malignancy of vinous tumor, comparative study with tubular adenoma as well as differentiated adenocarcinoma, should be performed with respect to cell kinetics, histomerrical analysis and so on.