Undifferentiated Pancreatic Carcinoma: Presentation, Classification and Prognosis

Undifferentiated pancreatic carcinoma, also called anaplastic pancreatic carcinoma or giant cells pancreatic carcinoma, is an uncommon and aggressive variety of ductal adenocarcinoma. Three types of undifferentiated carcinoma of the pancreas are known: Osteclastic-like giant cells tumor, pleomorphic giant cells tumor, and mixed giant cells tumor. Osteoclast-like giant cells tumor is characterized by the presence of large histocytic elements with many small nuclei showing no atypia. Pleomorphic giant cells tumor is characterized by the presence of bizarre mono- or multinucleated giant cells with atypical mitoses. The mixed giant cells tumor shows the simultaneous presence of both histological histotypes. The histogenesis of giant cells is controversial. Currently osteoclast-like giant cells are considered reactive elements deriving from a histiocytic lineage. Pleomorphic giant cells tumor originates from ductal epithelium with subsequent sarcomatous transformation. The various hystotypes show different behavior in terms of survival. Pleomorphic giant cells tumor is characterized by a worse prognosis than ductal adenocarcinoma while osteoclast-like giant cells tumor can be associated with longer survival time. The mixed giant cells tumor presents an intermediate prognosis. In conclusion, in case of undifferentiated pancreatic carcinoma, an accurate histopathological diagnosis can predict different behavioral pathways in terms of tumor progression and prognostic profile.