Sarcomatoid carcinoma of the stomach with osteoclast-like giant cells.

Carcinomas with osteoclast-like giant cells (OGCs) are a rare type of malignant tumor that is histologically characterized by the presence of multinucleated giant cells that resemble osteoclasts mixed with poorly differentiated adenocarcinoma cells. In this study, we report the clinicopathological and immunohistochemical features of a gastric sarcomatoid carcinoma with OGCs in a 37-year-old male. An abdominal CT scan demonstrated a large mass, measuring 15 cm × 10 cm, in the lesser curvature of the stomach. Microscopic examination revealed that the tumor was composed of sarcomatoid and carcinomatous elements with infiltrating OGCs. Immunohistochemical analysis showed that the sarcomatoid and carcinomatous elements were both variably positive for CK7 and EMA. The sarcomatoid components were also vimentin and SMA positive. This is the first report of a gastric sarcomatoid carcinoma with OGCs. The present tumor has progressed rapidly with extensive perigastric involvement and multiple intrahepatic metastases.