A case of osteoclast-like giant cell tumor of the pancreas

Osteoclast-like giant cell tumor of the pancreas is a very rare tumor. Despite their striking morphologic resemblance to certain mesenchymal tumors of bone and tendon sheath, it has been suggested that these tumors may arise from epithelial precursors. This unusual tumor presents in the 6th or 7th decade with a nearly equal gender ratio. Pure forms of osteoclast-like giant cell tumor have a better prognosis because they have a predilection to local spread, are slower to metastasize and rarely metastasize to lymph nodes, but these forms are very rare. We present an osteoclast-like giant cell tumor arising in the body of the pancreas in a 71 year-old male patient. The tumor was composed of two major cell types: atypical mononuclear cells and abundant osteoclast-like multinucleated giant cells. Immunohistochemical studies showed that atypical cells were strongly reactive for vimentin and focally reactive for cytokeratin. In contrast, the giant cells were immunoreactive for CD68, but negative for cytokeratin. Three months later, the tumor size increased and liver metastasis was newly developed. He died at 11 months after the diagnosis.