Carcinosarcoma and Multiple Early Gastric Carcinomas of the Stomach

ABSTRACT

We report a rare case of carcinosarcoma arising in the stomach. The tumor is presented in the posterior wall of the gastric lower body and antrum of a 56-year-old man. Grossly the tumor has polypoid appearance with diffuse surface ulceration and measures 5.5 cm in diameter. The tumor is accompanied with three separate well differentiated early gastric adenocarcinomas (two EGC type IIc & IIa). Microscopically, the tumor consists of moderately well differentiated adenocarcinoma in the periphery, and lobulated sarcomatous areas in the center, which shows chondroid differentiation. Transitional areas between adenocarcinoma and chondrosarcoma are evident. Immunohistochemical studies show positivity for cytokeratin and carcinoembryonic antigen in the epithelial component, and for vimentin and S-100 in the sarcomatous component. The transitional areas are positive in carcinoembryonic antigen, vimentin, S-100, and cytokeratin. The tumor extended to the subserosa and showed metastasis of only adenocarcinomatous component in six out of 47 dissected perigastric lymph nodes.