IIc＋IIa型直腸内分泌細胞癌（m癌）の1例

Type IIc＋IIa (Superficial Depressed Type) Intramucosal Endocrine Cell Carcinoma of the Rectum, Report of a Case

要旨　症例は62歳，男性．検診にて便潜血反応陽性となり大腸内視鏡検査施行．直腸に陥凹性病変を認め，精査入院となる．陥凹面の大部分は再生上皮粘膜で一部に腫瘍性病変を認め，生検にて内分泌細胞癌と診断．低位前方切除術を施行し，直腸（Rb），左壁の0-IIc＋IIa，癌部の大きさ2.5×2.0mm（非癌部を含めると11×9mm），m，ly1，v0，n0，stage0であった．本例は，内分泌細胞癌のみより形成される粘膜内癌であり，病変部において腺癌の合併は認めず，p53，Ki-67染色においても高異型度を呈していた．内分泌細胞癌の発生経路からも興味ある症例と思われ報告した．

　A62-year-old man visited our hospital for further examination concerning positive fecal occult blood in December, 2001. Colonoscopy revealed a Type IIc＋IIa (a depressed type) lesion in the rectum, measuring 11 mmin its largest diameter. The surface of the depressed area mostly appeared to be regenerating non-neoplastic mucosa, with signs of tumorous mucosa in part. The biopsy specimen of this lesion was diagnosed as endocrine cell carcinoma. Low anterior resection was performed. This case is a very rare case presenting intramucosal endocrine cell carcinoma, with no component of adenocarcinoma and showing proliferation of tumor cells by overexpression of p53 protein and staining for Ki-67.

　For this reason, the case was thought to be noteworthy for supplying information concerning the development of endocrine cell carcinoma.

　1) Division of Gastroenterology, Sapporo Kosei General Hospital, Sapporo, Japan

　2) Division of Clinical Pathology, Sapporo Kosei General Hospital, Sapporo, Japan