Gastric carcinoma with osteoclast-like giant cells.

Extraskeletal neoplasms with osteoclast-like giant cells are uncommon. These tumors are most frequently reported in the breast and pancreas, and are relatively rare in other sites. We report a case of primary gastric adenocarcinoma with an infiltrate of osteoclast-like giant cells. The patient is a 64-yr-old black woman who presented with epigastric pain and was found to have a mass in the gastric antrum. Histological examination showed a poorly differentiated adenocarcinoma with an infiltrate of osteoclast-like giant cells. The giant cells were present both in the primary gastric adenocarcinoma and in the lymph node metastases. Immunohistochemical stains demonstrated that the giant cells were of monocytic/histiocytic origin and probably represent a distinctive host response to the tumor. The patient is alive and well 12 months after resection. This is the second published report of gastric carcinoma with osteoclast-like giant cells. Based on this limited experience, gastric carcinoma with osteoclast-like giant cells may represent a distinct clinicopathological entity with a more favorable prognosis.