MIXED PLEOMORPHIC-OSTEOCLAST-LIKE TUMOR OF THE PANCREAS - LIGHT-MICROSCOPIC, IMMUNOHISTOCHEMICAL, AND MOLECULAR BIOLOGICAL STUDIES

The morphological, immunohistochemical, and molecular biological featu res of a case of giant cell tumor of the pancreas are described. This neoplasm showed mononuclear and multinucleated tumor giant cells as we ll as numerous osteoclast-like cells with multiple foci of osteoid-oss eous metaplasia. The pleomorphic and osteoclastic giant cells displaye d extensive homologies in their immunohistochemical profiles. Neither the pleomorphic nor osteoclast-like portion of the tumor showed neithe r c-Ki-ras nor p53 mutation and did not express the mutated p53 protei n. The results suggest that the pleomorphic and osteoclast-like compon ents are histogenetically related and that this rare neoplasm originat es from a precursor cell capable of differentiating along divergent ce ll type.