十二指腸に逸脱した巨大胃腺腫の1例

A Giant Gastric Adenoma Prolapsing into the Duodenal Bulb, Report of a Case

要旨　患者は78歳，女性で，心窩部痛，嘔気，嘔吐の出現後タール便がみられた．胃X線検査では十二指腸球部に逸脱した巨大な胃隆起性病変で，内視鏡では表面粗大顆粒状の巨大な乳頭状腫瘍であった．悪性を疑って胃幽門側切除術を施行した．腫瘍は9×8×5cmで表面は粗大顆粒状であるが柔らかく，潰瘍形成はみられなかった．組織学的には，腫瘍は多数の粘膜筋板の挙上を伴う小隆起性病変の集合したもので，核の濃染する高円柱状異型細胞の乳頭状ないし管状の増殖を示していた．明らかな癌化巣はみられず，胃大腸型腺腫（喜納，中村），papillotubular adenoma（WHO）と診断した．

　Papillary (vllous) adenoma of the stomach is somewhat rare and is associated with a high malignant potential.

　A 78-year-old woman was admitted to the hospital with complaints of epigastralgia, nausea, vomiting and tarry stool. Upper G-I series showed a large gastric mass prolapsing into the duodenal bulb (Figs. 1, 3 a and 3 b). Endoscopy revealed a large papillary tumor occupying the lower body and the antrum of the stomach (Fig. 2 a, b). Mutiple biopsies demonstrated only benign-appearing gastric mucosa with slight atypism. The stomach was resected after a clinical diagnosis of a giant gastric tumor with malignant change. The tumor was 9×8×5 cm in size and was well demarcated from the surrounding mucosa. It was soft and its color was slightly whitish. The surface of the tumor was irregularly nodular and lobulated without ulceration (Fig. 4 a, b).

　Histologically, the tumor was composed of many polypoid lesions with elevation of the muscularis mucosa (Fig. 4 c) and was diagnosed as gastric adenoma, colonic type (Kino, Nakamura) and papillotubular adenoma (WHO). Although elongated columnar cells with hyperchromatic nuclei showed slight atypism (Fig. 5 a-c) and a part near the surface showed rather severe cellular and structural atypism (Fig. 5 d), no evidence of carcinomatous change was recognized.