大腸原発性Linitis plastica癌―3例報告と文献的考察

Primary Linitis Plastica Carcinoma of the Colon: Report of three cases and review of literature

　“Linits plastica”癌という用語は，長い間胃に限って考えられ，使用されてきたが，1931年Coe¹⁾の記載により，腸のlinitis plastica癌が注目され始めた．すなわち，彼は胃のlinitis plastica癌の転移による左右結腸曲と直腸のsecondaryのlinitis plastica癌の1例を報告し，腸におけるこのような症例の記載はこれまで教科書やレ線関係文献にないとした．しかし，1936年Dixonら²⁾は，1つあるいはそれ以上の腸を侵すlinitis plastica癌をCoe以前の報告も含め37例引用し，自験症例6例と合わせ43例記載した．David（1931）³⁾の胃の状態に関する言及がない直腸の1例，および自験症例1例の胃空腸吻合術後11年経ても生存中の幽門および十二指腸第2部に病変があった症例（組織検査非施行）も含めているが，Dixonらはこれらはすべて胃癌の転移によるものと考えた．その後，今日まで約100例の大腸のsecondaryのlinitis plastica癌の報告をみているが，そのほとんどが胃癌，すなわち胃のlinitis plastica癌の転移によるものであり⁴⁾，ごくまれに乳癌⁵⁾，胆囊癌⁶⁾からの転移によるものが知られている．大腸原発性のlinitis plastica癌が初めて提起され，記載されたのは1951年のLaufman and Saphir⁷⁾の4例報告に始まる．その後，ごく最近まで29例の大腸原発性のlinitis plastica癌の報告をみるにすぎず（次頁Table 1），きわめてまれである．Fahlら⁸⁾によれば，1930年から1953年までの間にMayo Clinicで剔出された大腸癌12,000例のうち，11/例がlinitis plastica typeであったとしている．ただし，彼らはそれらに関して，大腸原発性である根拠は何も言及していない．また，Pineda and Bacon⁹⁾によれば，1,778例の大腸癌のうち3例がlinitis plastica癌で，そのうち1例は胃に悪性変化はなかったと記載している．primaryのものは勿論のことsecondaryのものもきわめてまれといえる．

　著者らは大腸原発性のlinitis plastica癌の3例を経験したので報告し，これまで報告された症例と合わせ，大腸原発性のlinitis plastica癌の臨床病理学的特微を検討した（剖検がなされていず，胃の状態に何ら言及がなされていない症例はprimaryの収載から除外した）．

　Primary linitis plastica carcinoma of the colon is extremely rare, and only 29 cases have been reported so far. Linitis plastica carcinoma of the colon should be diagnosed as primary only when the primary site of the stomach or breast is ruled out. Besides presenting our own three cases, we cited previously reported cases and reviewed the pertinent clinical, roentgenographic and pathologic features.

　In the series of 32 cases of primary linitis plastica carcinoma of the colon, 19 were males and 13 females (3:2). The youngest patient was 24 years old, the oldest 75, and the average was 55.0 (male 58.6, female 49.8). The majority of tumors were found in the rectum and sigmoid colon. Predominant symptoms were left lower abdominal cramps, constipation, diarrhea, ribbon-like stool or tenesmus ; these were mainly the obstructive symptoms of the left colon. Since the clinical mainfestations appeared late, the disease was far advanced when the patient was first seen, occasionally accompanied with weight loss, tumor resistance in the lower abdomen, ascites and rarely lymph node swelling. In many cases, symptoms were noticeable about three months before admission, much shorter than in usual colonic carcinoma.

　Roentgenographically, it was characteristic that primary linitis plastica carcinoma appeared more like an inflammatory lesion than a carcinoma. Considerably long segmental stenosis, rigidity and irregularity of the bowel wall, loss or thickening of mucosal folds, and lack of intraluminal filling defects were noted, but these were no specific features. The tapering of the colonic lumen in margins, loss of irritability and shortening of the mesentery were more noticeable.

　Grossly, linitis plastica carcinoma of the colon was characterized by the long (at least 6 cm), tube-like marked thickening and firmness of the wall, and intraluminaI narrowing. Gross findings of early stage of the disease have not been known.

　Microscopically, the disease was characterized by a diffusely infiltrating, mucous secreting anaplastic adenocarcinoma with varying amounts of scirrhous reaction. It spreads mostly to the lymphatics, or shows direct invasion and peritoneal dissemination with rapid downhill course.

　The prognosis was poor even if the wide resection was performed and the patients died mostly several months, simply because the tumors were not recognized in time.