Osteoclastic giant cell tumor of the pancreas. Aspiration cytology, light microscopy, and ultrastructure with review of the literature

The osteoclastic giant cell tumor of the pancreas is a rare primary neoplasm that by light and electron microscopy mimics giant cell tumor of bone. In the proper clinical setting, this lesion can be diagnosed by fine needle aspiration. Review of 10 cases reveals a female predominance, a median survival of 12 months, and a tendency for local invasion, rather than lymphatic or distant metastasis, and for invasion of large veins. An epithelial origin is favored for this malignant neoplasm, which expresses varying degrees of mesenchymal differentiation.