まれな大腸悪性腫瘍の病理診断

Pathology of Uncommon Malignant Lesion in the Large Intestine

要旨●びまん浸潤型（いわゆる4型）大腸癌と肛門管に発生した悪性腫瘍，大腸内分泌細胞癌の肉眼所見ならびに病理所見について，当院で診断した症例を提示しながら解説した．4型大腸癌は組織学的に癌性リンパ管症が目立つlymphangiosis（LA）型と，高度な線維性間質反応を伴うscirrhous（SC）型，粘液結節の豊富な粘液癌が腸管壁全層に浸潤増殖するmuconodular（MN）型，腫瘍先進部やその近傍に著明な慢性炎症細胞浸潤や小膿瘍を形成するinflammatory（IF）型の4型に分けて，それぞれの組織型に近いと考えられる症例を提示した．肛門管に発生した悪性腫瘍については，直腸型腺癌，pagetoid spreadした腺癌，Crohn病に合併した痔瘻癌，扁平上皮癌，悪性黒色腫の組織像を提示した．大腸内分泌細胞癌については自験例10例の臨床病理学的事項をまとめ，その組織像ならびに肉眼像を提示した．

　We explained histopathological features of diffusely infiltrating（so-called type 4）primary colorectal cancers, that of malignant tumors arising in anal canal and that of endocrine carcinomas of the colorectum. Type 4 colorectal carcinoma is classified into 4 histological types, such as lymphangiosis（LA）type, scirrhous（SC）type, muconodular（MN）type and inflammatory（IF）t type. LA type is characterized by prominent lymphatic permeation. SC type is accompanied by marked dense desmoplastic reaction, like gastric scirrhous carcinoma. MN type is composed by massive mucin lakes with carcinoma cells through the colorectal wall. IF type is characterized by transmural massive chronic inflammatory infiltrate, severe mural fibrosis and abscess formation in the invasive front. We presented the cases of these types, which were we previously diagnosed in our institute. As to the malignant tumors arising in anal canal, we present the cases of adenocarcinoma including Pagetoid spread and mucinous adenocarcinoma arising in anal fistula associated Crohn's disease, squamous cell carcinoma and malignant melanoma. Moreover, we mentioned about histological and clinicopathological features of colorectal endocrine carcinoma. We presented the features of 10 our cases of colorectal endocrine carcinoma.