Clinicopathologic study on pancreatic cancer associated with pancreatic stones.

Four cases of pancreatic cancer associated with pancreatic stones were investigated clinicopathologically. In Case 1, pancreatic cancer was diagnosed 2 yr 9 mo after the diagnosis of pancreatolithiasis. Numerous large stones were present throughout the pancreas, and stones in the resected specimen were embedded in the tumor. Chronic inflammation, including inflammatory infiltration and fibrosis, were found around the pancreatic duct where the stones were present, both within and adjacent to the tumor, suggesting that chronic pancreatitis had been present for a protracted period. In Cases 2-4, a few small free stones were found in the dilated pancreatic ducts and a cyst upstream from the tumor, but there were no stones noted within the tumor. Microscopically, mild atrophy of the pancreatic parenchyma and fibrosis were seen. In each of these three cases, it was considered that the pancreatic cancer was the primary event, with the pancreatic stones arising as a secondary process. The pancreatic cancers associated with pancreatic stones were classified into two groups, one with pancreatic stones preceding the pancreatic cancer and the other three cases in which the reverse occurred.