Osteoclast-like giant cell tumor of the pancreas: immunophenotypic similarity to giant cell tumor of bone.

An immunophenotype was performed on an osteoclast-like giant cell tumor of the pancreas using a panel of antibodies to epithelial and leukocyte antigens. Several antibodies to cytokeratin and carcinoembryonic antigen were negative in the tumor. Osteoclast-like cells were positive for CD4, CD13, CD45, CD68, CD71, and vimentin, but negative for lysozyme and HLA-DR. Mononuclear tumor cells were positive for CD4, CD11c, CD13, CD14, CD45, CD68, CD71, HLA-DR, and vimentin, but negative for lysozyme. The phenotype is similar to that previously described for giant cell tumor of bone. The osteoclast-like cell phenotype is also similar to that reported for normal osteoclasts. The findings support a nonepithelial origin for osteoclast-like giant cell tumor of the pancreas, and suggest a derivation similar to giant cell tumor of bone.