Immunohistochemical and Genetic Analysis of Osteoclastic Giant Cell Tumor of the Pancreas

Abstract

Clinical, histopathologic, immunohistochemical, and genetic analyses of 2 osteoclastic giant cell tumors of the pancreas are presented. The neoplasms were composed of osteoclastic giant cells and pleomorphic cells (PCs). The tissue-specific markers gave evidence of mesenchymal nature of the osteoclastic giant cells, as well as other components of the tumor, and lacked any signs of epithelial differentiation in both patients. The nonepithelial nature of both components in the osteoclastic giant cell tumors presented may be associated with a better prognosis, which corresponds to the previous reports of similar neoplasms. A positive immunoreactivity to neuron-specific enolase was recorded in patient 2. The presence of CD68 in osteoclastic giant cells proved their histiocytic nature. Both components of the tumors showed a negative immunoreactivity to desmin and only a scattered reactivity to smooth muscle cell actin, typical markers of myofibroblastic differentiation. Mutation analysis of the tumor revealed the wild state of both p53 and K-ras oncogenes in both patients. A positive immunoreactivity for p53 in PCs of both osteoclastic giant cell tumors was recorded, whereas osteoclastic giant cells did not express this protein. The expression of p21 was recorded in osteoclastic giant cells in patient 1. The absence of Ki-67 in the osteoclastic giant cells and its expression in PCs gave evidence of a different proliferation rate of both cell populations. Different tissue-specific markers, a different proliferation rate, and a different state of oncogene activation in the osteoclastic giant cell tumors contribute to the idea that the tumor derives from a pluripotent cell that may differentiate into an array of phenotypes.

Undifferentiated carcinoma of the head of pancreas with osteoclast-like giant cells presenting as a symptomatic cystic mass, following acute pancreatitis: Case report and review of the literature

“…Studies on light and electron microscopy, on immunophenotype of the tumor cells and molecular biology analysis, have been used to support a mesenchymal or an epithelial origin of the tumor [16] , [17] . Some authors contributed the idea that it arises from a precursor pluripotent cell that may differentiate to distinctive phenotypes [2] , [16] , while others consider it carcinosarcoma-like neoplasm that consists of both epithelial and histiocytic-mesenchymal component [7] , [17] . Acinar cell origin or derivation from a mucinous cystic neoplasm or from ductal cells have also been discussed [4] , [5] .…”

Undifferentiated Carcinoma With Osteoclastic Giant Cells of the Pancreas

“…The overall impression in the literature is that it is a highly aggressive tumor, with an even worse prognosis than ordinary pancreatic ductal adenocarcinoma (4–7) although some observers noted a more protracted course. This is partly attributable to the fact that pleomorphic undifferentiated carcinomas of NOS type (poorly differentiated version of ductal adenocarcinomas) have often been classified and analyzed along with OGCs.…”

Pancreatic undifferentiated carcinoma with osteoclast-like giant cells curatively resected after pembrolizumab therapy for lung metastases: a case report

“…UCOGC is a rare variant of PDAC having a unique morphology which is composed of non-neoplastic cells (OGCs) and neoplastic cells (spindle and pleomorphic cells) without a definitive direction of differentiation [ 14 , 15 ]. UCOGC used to be considered as an aggressive type of PC, because of the confusion of other “undifferentiated” carcinoma derived from PDAC, mucinous neoplasms and anaplastic carcinoma [ 16 , 17 ]. Recent studies investigated the clinical and pathological features of pure UCOGC and concluded that patients with UCOGC had a significantly better prognosis than that with conventional PDAC or UCOGC derived from PDAC [ 2 , 3 ], although the genetic alterations in UCOGC are notably similar to ordinary PDAC [ 3 ].…”