病巣の中心部にポリープ状隆起を生じた胃の印環細胞癌の1例

Polypoid Growth in Signet-ring Cell Carcinoma of the Stomach, Report of a Case

要旨　印環細胞癌から成る特殊な形の隆起型胃癌の1例を報告した．患者は55歳の女性．1981年11月，胃の集団検診で異常を指摘され，精査の結果胃癌と診断．1982年2月幽門側胃切除術を施行した．病変は幽門前庭部後壁にあり，40×25mm径の粘膜下腫瘍様の隆起の中心部に，示指頭大のポリープ状隆起がみられた．病理組織学的には，ポリープ状隆起は印環細胞癌のみから成り，粘膜下層では著しいfibrosisを伴い，局在性硬癌の所見を呈していた（H₀P₀n₀se）．印環細胞癌がこのように隆起型の発育をすることは極めてまれであり，その成り立ちについて考察を加えた．

　The appearance of polypoid growth is extremely rare in cases of signet-ring cell carcinoma of the stomach.

　In this report, we describe an unusual case of signet-ring cell carcinoma in which the tumor grew intraluminally and gave a nipple-like, polypoid appearance on x-ray and endoscopy (Fig. 1～Fig. 4). The tumor also infiltrated deeply in the wall but was localized. To our knowledge, no similar, well documented cases have been reported previously.

　The case history is as follows: The patient, a 55 year-old woman, was admitted to the hospital because of evaluation of a polypoid lesion of the stomach, which was found incidentally on x-ray mass screening for gastric cancer. Roentgenographic and endoscopic examination of the stomach showed an elevated lesion, 4.0×2.5 cm in size, having a nipple-like polypoid projection in the midst of the lesion. Biopsy showed signet-ring cell carcinoma. A subtotal gastrectomy was performed.

　Histologically, the polypoid lesion noted above was composed entirely of signet-ring cell carcinoma with infiltration to the deep layer of the gastric wall. Serial study of the polypoid lesion revealed no remnants of non-neoplastic mucosal epithelium or malignant glandular structure. In addition, a lipoma (1.8×1.5 cm) and a small hyperplastic polyp coexisted separately.