KRAS oncogene mutations suggest a common histogenetic origin for pleomorphic giant cell tumor of the pancreas, osteoclastoma of the pancreas, and pancreatic duct adenocarcinoma

Giant cell neoplasms of the pancreas are rare tumors of uncertain histogenesis. Mutation of the KRAS oncogene is common in typical pancreatic duet adenocarcinoma. We have analyzed DNA from five pancreatic tumors with giant cells for mutations in the KRAS oncogene and found alterations of the second position of codon 12 in each case (four G > A transitions and one G > C transversion). The common mutation pattern in tumors with giant cells and duct adenocarcinoma suggests a common route to malignant transformation and may indicate a shared histogenesis. We also tested 11 cases of malignant fibrous histiocytoma, a histological mimic of pleomorphic giant cell tumor, for mutations in the KRAS oncogene. The absence of KRAS mutations in each of the malignant fibrous histiocytomas (MFHs) and in other histologically similar tumors may provide assistance in the differential diagnosis of pleomoyphic pancreatic tumors.