Clinical and pathological features of undifferentiated pancreatic carcinoma with osteoclastic giant cells: a rare case.

Undifferentiated pancreatic carcinoma with osteoclastic giant cells (UOC) is a rare pancreatic malignancy composed of three unique cell types. Currently, the histopathologic origin of UOCs remains unclear. Some studies considered that it was differentiated from epithelial tissues, while others favored a mesenchymal derivation. We present the case of a 59-year-old UOC patient with a tumor (3.0 cm×3.0 cm×2.5cm) in the pancreatic neck. He underwent an en-bloc resection of the distal pancreas associated with the spleen. Light microscopic examination revealed two typical types of UOC cells, with one type absent. The immunohistochemical staining was positive for pancytokeratin, epithelial membrane antigen, vimentin and cluster of differentiation 68, which indicated different derivations for these two kinds of cells. UOC is a rare condition with unique imaging and pathological features. Endoscopic ultrasonography and fine needle aspiration are dispensable preoperatively. Radical resection should be tried for UOC treatments. In our opinion, osteoclastic giant cells are reactive cells derived from histocytes. The case presented here will be of interest to the whole UOC cohort.