A case of intraductal papillary adenocarcinoma of the pancreas associated with mass forming chronic pancreatitis without calcifications is described. Pancreatolithiasis, or calcified pancreas, is recognized as a high risk factor for pancreatic cancer. However, epidemiologic studies have found that carcinoma of the pancreas associated with chronic pancreatitis was rare. The question is whether chronic pancreatitis without calcifications is actually a precancerous background lesion or not. This case suggests that hyperplasia of the pancreatic ductal epithelium may be a precancerous lesion for pancreatic cancer in some patients with chronic pancreatitis.