注腸X線，内視鏡検査で経過の追えた大腸sm癌の1例

Submucosal Cancer which Could Have Been Followed by Barium Enema and Colonoscopy, Report of a Case

要旨　症例は65歳，男性．初回の注腸X線，内視鏡検査および生検では，盲腸に長径13mmの隆起型腺腫が診断されていた．33か月後の最終の注腸X線，内視鏡検査では，初回検査と同じ場所に長径19mmの2型進行癌類似の形態を示したsm massive癌が診断された．回盲部切除が施行された．病理組織学的には，大きさ16×14mm，2型進行癌類似型，深達度sm₃の腺腫を伴う高分化腺癌と診断された．発育形式は，ほとんどの部分がnon-polypoid growth（NPG）typeであったが，粘膜内のごく一部に周囲よりも丈の高い腺腫を認め，polypoid growth（PG）typeと判定された．adenoma-carcinoma sequenceによる癌化の形態変化のみならずPG-typeからNPG-typeへ移行する過程も捉えられた病変と推察された．なお，注腸X線フイルム上の計測から計算された体積倍加時間は，20.2か月だった．

　A 65-year-old male was diagnosed by barium enema examination and colonoscopy as having a type 2-like cancer, 19 mm in size, in the cecum, the same site where an adenoma had been found at the initial examination 33 months previously. An ileocecal resection was performed. The tumor was 16 × 14 mm in size and the morphologic feature was similar to type 2 advanced cancer. Pathologically, the tumor was a well differentiated adenocarcinoma having an adenomatous component invading the deepest layer of the submucosa (sm₃) . As adenoma was found only in part of the remaining mucosa, the growth type was thought to be polypoidgrowth (PG) type. Thirty-three months earlier the patient had been diagnosed by barium enema, colonoscopy and endoscopic biopsy as having a protruded type adenoma, 13 mm in size, in the cecum. It was considered that we had been able to observe in this case not only the morphologic change through the adenoma-carcinoma sequence but also the changing process from PG-type to non-polypoid growth (NPG) type. Doubling time calculated by measurement on radiographs was 20.2 months.

　Much more case documentation with barium enema and endoscopy is necessary to clucidate the natural history of colorectal cancer and adenoma.