胃過形成性ポリープより発生した低分化腺癌の1例

Poorly Differentiated Adenocarcinoma Developed in a Hyperplastic Polyp of the Stomach, Report of a Case

要旨　患者は65歳，女性．主訴は貧血．胃X線および内視鏡検査にて胃体中部前壁に2.5×4.0cm大の，胃体下部後壁に2.0×3.0cm大の山田Ⅳ型のポリープを認めた．ポリープ頭部の生検では両者とも過形成性上皮が得られたが，前者のポリープの茎部に認められたⅡc様陥凹面からsignet-ring cellを伴う低分化腺癌が得られたため，胃全摘術を施行した．組織学的に前者のポリープの頭部では腺窩上皮がかなりの部分で高分化腺癌に置き換わると共に，粘膜固有層内には同様の核を有する腺管を形成しない癌細胞の増生を認め，更に茎部は大部分が低分化腺癌から構成されていた．本例は過形成性ポリープから低分化腺癌が発生した極めてまれな症例と考えられた．

　A 65-year-old female presented to us with anemia. Upper GI barium study and endoscopic examination revealed two Yamada type IV polyps in the gastric body. One of the polyps was a hyperplastic polyp, but the other was composed of both hyperplastic and carcinomatous tissue. In the latter polyp, the hyperplastic foveolar epithelium was partly replaced by well differentiated adenocarcinoma, and the large part of the proper mucosal layer consisted of poorly differentiated adenocarcinoma with signet-ring cells. This case is thought to be very rare in that poorly differentiated adenocarcinoma may have developed in a hyperplastic polyp of the stomach.