Needle aspiration cytology, immunocytochemistry, and electron microscopic study of unusual pancreatic carcinoma with pleomorphic giant cells.

Needle aspiration cytology, immunocytochemistry, and electron-microscopic findings are presented in three cases of an unusual pancreatic carcinoma in which pleomorphic giant cells formed an integral part of the tumour. All three patients were elderly males (age range 66-83 years) and had pancreatic masses. Notable cytologic features in all cases were the presence of bizarre mononucleated and multinucleated, poorly cohesive tumour giant cells, rare spindle cells, with occasional cannibalism and cytophagocytosis. Immunocytochemical study of aspirated material showed diffuse staining of cytokeratin and EMA within the tumour cells, while B 72.3 was seen as focal trace stain. Electron microscopy of aspirated material demonstrated epithelial features and these were characterised by the presence of tonofilaments and surface microvilli. Based on our findings, it is felt that the bizarre giant cells in this unusual variant of pancreatic carcinoma are of epithelial origin. The differential diagnosis of other tumours that may be associated with predominant giant cells in pancreatic aspirates is appropriately discussed.