- Five cases of pancreatic neoplasms accompanied by production of alpha-fetoprotein (AFP) and serum elevation of this marker are presented, and the better-documented cases of this phenomenon from the literature are reviewed. Four of the cases originated in the orthotopic pancreas, whereas the fifth arose in the pancreatic component of a mediastinal teratoma. The patients were children or young adults. AFP production in pancreatic tumors is closely linked to acinar differentiation, most cases representing either pancreatoblastoma or acinar cell carcinoma. The distinction between these 2 tumors may be difficult because of the many morphologic and immunohistochemical features they share. HUM PATHOL 31:938-944.