X線像によるretrospectiveな検討からみた大腸腫瘍の自然史

Retrospective Investigation on the Natural History of Colorectal Tumors

要旨　大腸腫瘍の自然史は病変ごとにそれぞれ異なっている．だが，大腸腫瘍の自然史，特に進行大腸癌への自然史には，共通性もみられる．X線像による遡及的検討の結果，6mm以上の病変では，無茎や扁平な表面隆起型の病変から進行癌に発育するのが，主経路であろうと再確認できた．今回更に，①同じ個体で同じ部位に発生した腫瘍でも，それぞれ発育・進展とdoubling timeは異なっている．②Is型の早期癌には形態的にみて，主に分葉状，結節状およびその中間状の病変がある．結節状のⅠs型癌は，癌がsmに深く多量に浸潤した病変が多く，また早急に進行癌へ推移しやすい．③潰瘍浸潤型（3型）に推移した3病変の初期形態は，それぞれⅡa型，結節集簇から成るⅡa様，Ⅰs型病変であった．④画像とともに組織学的な経過が得られた2症例3病変の検討で，すべて経時的に異型度が増していた．また，腺腫から腺癌へ進みうる症例があることを実例をもって示した．

　The natural history of colorectal tumor differs among lesions, however, there may be common natural history of colorectal tumors, especially in developing advanced colorectal cancer. Retrospective analysis by the radiologic examination re-confirmed that the majority of advanced carcinoma would evolve from non-sessile or flat elevated lesions. The other findings we reported in this article were summarized as follows: 1) The growth and development, and doubling time differed even in the lesions of the same location and the same individual. 2) The type Is early cancer was macroscopically classified as the lobulated, nodular and intermediate types. The nodular type cancers tended to be accompanied by massive and deep sm invasion and rapidly develop into advanced lesion. 3) Three original lesions which developd into type 3 advanced cancers were type Ⅱa, nodular aggregating and type Ⅰs lesions initially. 4) Three lesions from two cases which were follwed by both macroscopic and microscopic examinations chronologically disclosed that degree of atypia increased with time and adenoma evolved into adenocarcinoma.