Undifferentiated pancreatic carcinoma with osteoclast-like giant cells: report of a case with osteochondroid differentiation.

We report a case of an undifferentiated pancreatic carcinoma with osteoclast-like giant cells with focal osteochondroid differentiation in a 66-year-old man, who presented with painless jaundice, pruritus, and weight loss. Imaging studies revealed an inhomogeneous mass in the head of the pancreas. A pylorus preserving pancreaticoduodenectomy was performed. The resection specimen revealed a 9.5 x 4.2 x 3.2 cm(3) solid neoplasm in the pancreatic head with direct extension into duodenum and common bile duct. Microscopy showed a cellular neoplasm composed of pleomorphic mononuclear cells (pancytokeratin, and EMA-positive; LCA, and CD68 negative) and osteoclast-like multinucleated giant cells (vimentin, LCA, and CD68-positive; pancytokeratin, and EMA-negative) consistent with OGTP. The tumor contained a focal area of osteochondroid differentiation. Evidence supports that the tumor giant cells are non-neoplastic and of histiocytic origin. Osteochondroid differentiation within undifferentiated carcinoma is unusual; its presence might suggest a sarcoma diagnosis on biopsy material.