特異な形態を呈した胃のhamartomatous inverted polypの1例

Hamartomatous Inverted Polyp Associated with Hyperplastic Polyp of the Stomach, Report of a Case

要旨　患者は，40歳，女性．胃X線検査では，胃穹窿部大彎に大きなだるま状の隆起性病変を認めた．基部は広基性で表面平滑，頂部は表面不整で結節状を呈していた．内視鏡検査では，基部はやや青白色で健常粘膜に覆われ，クッションサインを認めた．頂部に過形成性ポリープ（HP）を伴う軟らかい粘膜下腫瘍と診断した．EUSでは，頂上隆起部および粘膜下腫瘍上層部に一致して，第2～3層内に高エコー域と多発小無エコーの混在を伴う低エコー域を認めた．更に粘膜下腫瘍深層部に一致して隔壁を有する大きな無エコー域を認めた．基部に関してはhamartomatous inverted polyp（HIP），リンパ管腫などを疑った．確定診断のため，内視鏡的ポリペクトミーを施行した．組織学的には頂上隆起部はHP，基部はHIPであった．本症例の特殊形態の成り立ちとして，粘膜下の異所性胃腺が粘膜内に侵入後，物理的刺激により二次的にHPが形成されたものと推察された．

　A 37-year-old female attended our hospital for further examination of a gastric protrusion discovered during a health check. X-ray examination showed a unique protrusion shaped like a daruma. Endoscopic examination revealed a pale submucosal tumor associated with a reddish nodule at the greater curvature of the fornix. A regular groove-like pattern was seen on this noduler lesion. Endoscopic ultrasonography showed diffuse high-echo pattern in the nodule and multilobuler nearly anechoic pattern in the submucosal tumor. Endoscopic polypectomy was performed. Much whitish mucus exuded. On the cut surface of the resected specimen, multiple cysts were observed except on the surface of the nodular lesion. Histological section revealed that these tumors had primarily consisted of various-sized cystic glands. Each gland consisted of non-atypical epithelium. We, therefore, guess that, initially, a hamartomatous inverted polyp had existed and hyperplastic polyp was formed secondarily.