Gastric carcinoma with osteoclast-like giant cells. Report of four cases.

Four cases of gastric carcinoma are described that are associated with an osteoclast-like giant cell (OGC) stromal component. The patients were all middle-aged men (range 53-63 years). Microscopically, the tumors were characterized by a bland cytologic appearance, and an either solid or cribriform pattern. Osteoclast-like giant cells were found adjacent to, or intimately intermixed with, the neoplastic cells in the primary gastric masses and in the lymph nodal metastases and were often associated with lymphocytes, histiocytes, and desmoplastic stroma. By immunohistochemistry, mononuclear cells and OGCs showed diffuse positivity for alpha-1-antichymotrypsin, alpha-1-antitrypsin, and CD68. Neoplastic cells that were positive for keratin and CEA, also showed reactivity for vimentin and the latent membrane protein of Epstein-Barr virus in one case. At follow-up, three patients had died at 13, 15, and 24 months after diagnosis, and one is still alive, without evidence of disease, after 120 months. This report describes a novel variant of gastric carcinoma with distinctive and histologic features.