多彩な肉眼像を呈する表層拡大型胃癌の1例

Superficial Spreading Type of Gastric Cancer with a Singular Macroscopic Feature, Report of a Case

要旨　患者は62歳の女性で，特に症状はなかったが胃X線透視で胃体中部から前庭部に大小の隆起性病変が多発していた．内視鏡検査でも同様の所見であったが，入院後10日の経過で口側境界部後壁に潰瘍性病変が出現した．摘出標本肉眼所見では，Ⅱa集簇型，Ⅰ型，Ⅱc型，Ⅱc＋Ⅲ型の複雑な所見を呈していた．組織学的には胃固有腺窩上皮に類似した高分化型管状腺癌が主体であったが，多くの切片で粘膜固有層上層部は分化型癌，下層部は未分化型癌という2層構造がみられた．また，隆起間粘膜には腸上皮化生性上皮に囲まれた微小癌化巣（Ⅱb型）がみられた．深達度はⅡc＋Ⅲ型とした部のみがsmで他の部はmであった．

　Screening x-ray study and subsequent endoscopic examination of upper gastrointestinal tract were performed on a 62-year-old woman with no subjective symptoms. Upper gastrointestinal series showed multiple polypoid lesions of varying size from the middle body to the antrum of the stomach. Endoscopy confirmed these findings, but an ulcerative lesion was noted at the oral margin of the lesions in the posterior wall 10 days after she was admitted.

　Resected specimen showed complicated macroscopic findings of type Ⅱa (confluent type), Ⅰ, Ⅱc and Ⅱc + Ⅲ. Histologic examination revealed well differentiated tubular adenocarcinoma resembling to gastric foveolar epithelium as a main histologic type. However, there were two-layer structures of differentiated and undifferentiated types in many portions. Furthermore, there were many foci of microscopic cancerous follicle surrounded by metaplastic mucosa (type Ⅱb) between the polypoid lesions. Depth of invasion was sm only at the site of type Ⅱc + Ⅲ, and that for other types was m. Metastasis to "n₂" lymph node was demonstrated.