十二指腸球部Ⅱa型早期癌の1例

Early Duodenal Cancer Supposedly Arising from the Brunner's Gland, Report of a Case

要旨　患者は45歳，女性．主訴は上腹部痛．入院時理学的および血液・生化学検査では特に異常を認めなかった．上部消化管X線検査では十二指腸球部前壁から小彎にかけて結節状で境界明瞭な扁平隆起を認めた．内視鏡検査では，一部に粗大結節を伴う大小不同の隆起で，表面に発赤を伴い，生検にてGroup Ⅴと診断された．切除標本では，大きさ1.9×1.4cmで組織学的には深達度mの高分化型腺癌であった．癌巣周囲には組織学的に幽門腺化生などは認められず，また癌細胞の分化形質を粘液組織染色〔paradoxical concanavalin A（Con A）染色，galactose oxidase-Schiff（GOS）染色，sialidase-GOS（S-GOS）染色〕およびペプシノーゲン（PgⅠ，Ⅱ）免疫組織染色を用い検討した結果，本症例はBrunner腺より発生した十二指腸癌と考えられた．

　A 45-year-old woman was admitted to our hospital for a further examination of a duodenal lesion noted at Sugimura clinic. Barium x-ray and endoscopy revealed a flat polypoid lesion with nodular and slightly reddish surface, most of which was located in the anterior wall of the duodenal bulb growing toward the lesser curvature. This lesion was thus thought to be early cancer limited at most to the submucosal layer of the duodenum. The lesion was histologically adenocarcinoma on biopsy specimens.

　Examination of the material resected by partial duodenogastrectomy showed that the lesion, 19×14 mm in size, was histologically well differentiated tubular adenocarcinoma invading into the mucosal layer without metastasis to the adjacent lymphnodes. Mucin histochemistry and pepsinogen (Pg) immunohistochemistry were employed to define phenotypic expression of duodenal cancer cells, demonstrating intracellular mucin of class Ⅲ because it was stained positively by paradoxical concanavalin A, but not by the galactose oxidase-Schiff and sialidase-galactose oxidase-Schiff staining; cytosolic Pg was stained positively by anti-Pg Ⅱ, but not by anti-Pg Ⅰ, antibody. Furthermore, there was no pyloric gland metaplasia in the duodenal mucosa surrounding the lesion on histologic specimens obtained from the duodenum resected. These findings strongly suggested that this duodenal cancer arose primanriy from the Brunner's gland. Early duodenal cancer implicating its cellular origin has been very rarely reported up to date.