骨化生を合併した原発性S状結腸硬性癌の1例

Primary Scirrhous Carcinoma of the Sigmoid Colon Associated with Osseous Metaplasia, Report of a Case

　大腸におけるlinitis plastica型硬性癌の頻度は非常に少なく^{1)2)7)9)10)～12)14)15)19)20)}，いまだその特徴がはっきり浮き彫りにされていない．この型の癌は，X線像，内視鏡像，肉眼像からは原発性，続発性の区別が非常に難しく¹¹⁾，また炎症性疾患との鑑別が重要とされている¹²⁾²¹⁾．

　また，大腸における腺腫の癌化は，様々の情況証拠から多くの研究者により支持されているが^4)13)17)，癌が進行するとその先行病変の痕跡をたどることが困難な場合が多い．

　We report here a case of primary scirrhous carcinoma arising in the sigmoid colon which was associated with osseous metaplasia.

　This 79-year-old man was admitted to our hospital complaining chiefly of a dull pain in the lower left region of the abdomen and of lumbago. The first barium enema revealed segmental narrowing of the sigmoid colon due to a 15 cm long carcinoma showing prominent irregularity at its margin. Three weeks later, it began to show an increased narrowing and stiffness with an oppressed figure in a circular arc. The CT showed a thickening of the wall and a comma-shaped calcified lesion. The inferior mesenteric angiography showed remarkable encasement in the main trunk of the inferior mesenteric artery and the branch of the left colic and sigmoidal arteries in the arterial phase. Endoscopic findings showed remarkable narrowing at the sigmoid colon, 40 cm oral from the anal verge. At the anal margin of this narrowing was an irregular, nodular protuberance, but with the same glistening and color in its surface as in the adjacent normal mucosa. Biopsy obtained from this portion revealed clusters of cancer cells in the submucosal lymphatics accompanied by remarkable stromal desmoplasia below the intact mucosa. Operative findings showed an anular narrowing tumor 13 cm the length of the sigmoid colon, which invaded the retroperitoneum with metastasis to paraaortic lymph nodes. Gross features of the resected specimen showed an anular narrowing portion of the sigmoid colon, showing prominent thickening of the wall and a cobblestone-like appearance in its mucosal surface with a brownish thumb-tip-sized protuberance at the center. Histologically, the mucosa was kept intact except for very limited parts, where adenocarcinoma and adenoma were observed. The brownish mucosal protuberance showed adenoma, in which adenocarcinoma coexisted. There was found to be a diffuse cancerous invasion with a predominant pattern of moderately differentiated adenocarcinoma accompanied by remarkable desmoplasia as well as lymphatic permeation through the entire wall below the submucosal layer. Benign osseous metaplasia was found in and around the cancerous invasion of the invaded mesosigmoid.