胃の衝突型横紋筋肉腫・腺癌混合腫瘍の1例

A Case of Mixed Rhabdomyosarcoma and Adenocarcinoma of Collision Type Occurred in the Stomach

　同一胃に癌腫と肉腫が共存する例はまれであるが，その多くは両腫瘍細胞が混じり合って，1つの腫瘍実質を形成している，いわゆる癌肉腫として報告されている．われわれは，胃肉腫の疑診のもとに胃切除術を施行し，病理組織学的検索により，衝突型の横紋筋肉腫と腺癌の混合腫瘍であった1例を経験したので，若干の考察を加えて報告する．

症例

　患　者：47歳　女性

　既往歴：特記すべきことはなし

　家族歴：母，72歳，胃癌で死亡

　主　訴：腹部腫瘤，下血

　現病歴：1973年11月頃より全身俗怠感があり，1974年2月初め頃より時々空腹時および食直後に上腹部の不快感，鈍痛があった，6月初め頃左上腹部に腫瘤を触れ，6月4日某病院に入院した．高度の貧血と胃透視における異常所見を指摘され，同年6月8日当科に入院した．

　A 47-year-old female was admitted to our hospital with melena and a palpable mass in the upper abdomen. The upper gastrointestinal X-ray series and endoscopic study demonstrated a huge protruding tumor in the antrum of the stomach. The tumor was palliatively removed by partial gastrectomy.

　During the surgical intervention, numerous lymph nodes swollen to the size of bean to hen-egg were noticed. In addition, a hen-egg sized metastatic tumor was also found in the left lobe of the liver.

　Grossly, the resected stomach revealed a large elevated, elastic soft tumor, measuring 9.5×9.0×7.0 cm.

　The margins of the tumor were raised, and its base was constricted.

　Histology proved that the tumor was a mixed tumor consisting of a rhabdomyosarcomatous and an adenocarcinomatous elements. Most part of tumor showed an embryonal pattern of rhabdomyosarcoma, while the base and the skirt of the tumor consisted of a well differentiated adenocarcinoma that was invading the muscularis propria.

　Although the two tumor elements were intermixed with each other, no transition was demonstrated between each of these two cellular elements. The tumor should be regarded as collision tumor.

　Metastatic foci of the liver and the lymph nodes contained metastasis from the well-differentiated papillotubularcarcinoma alone. No rhabdomyosarcomatous elements were identifiable.