S状結腸にみられた特殊な形態を呈したPeutz-Jeghers型ポリープ由来腺腫内癌の1例

Peutz-Jeghers Type Polyp with Submucosal Tumor-like Ridge and Carcinoma within Adenoma in the Sigmoid Colon, Report of a Case

要旨●患者は40歳代，男性．S状結腸に35mm大の発赤調の有茎性病変を認め，茎部にはSMT様の隆起を伴っていた．拡大観察では発赤部は非腫瘍性腺管領域と腫瘍性腺管領域の混在を認め，一部に不整な腺管構造を認めた．一元的な解釈は困難であったが，腺腫内癌および粘膜下浸潤あるいは粘膜下偽浸潤の可能性があると考えた．内視鏡的切除は可能と判断し診断的治療目的にEMRにて一括切除した．病理診断は，adenocarcinoma in adenoma arising in Peutz-Jeghers type polypと粘液湖形成を伴う粘膜下偽浸潤であった．

　We present the case of a man in his 40s, who had undergone colonoscopy for the evaluation of a colon polyp. A 35-mm pedunculated polyp with a reddish head was located at the proximal sigmoid colon. The stalk was swollen to form a submucosal tumor-like ridge. The magnified views of colonoscopy revealed several components ; some areas with a round pit pattern were suspected as non-neoplastic areas and some areas with a mixture of straight and branched pit patterns with an irregular pit pattern within were suspected as neoplastic regions. A submucosal tumor-like ridge on the stalk may represent cancer invasion or pseudoinvasion. It was difficult to establish a clinical diagnosis ; however, as a whole, we suspected that the polyp was a carcinoma in adenoma and judged that endoscopic resection was possible. En bloc endoscopic mucosal resection was performed. The pathological diagnosis was adenocarcinoma in adenoma arising in a Peutz-Jeghers-type polyp and pseudoinvasion with marked mucus retention within the inverted non-neoplastic endothelium.