We report an unusual case of gastric tumor: a stromal tumor with osteoclast-like giant cells. This type of cells has been described in epithelial tumors, especially in adenocarcinoma of the pancreas, lung, thyroid and breast. It has also been reported in smooth cell tumors such as uterine leiomyosarcoma and malignant fibrous histiocytoma. In our patient, this gastric stromal tumor with osteoclast-like giant cells was diagnosed in a man with adenocarcinoma of the colon in the context of a familial cancer syndrome. This is the first report of stromal tumor with osteoclast-like giant cells associated with Lynch syndrome.