[Histopathological study on branches of the pancreatic duct in obstructive pancreatic disorders].

Branches of the pancreatic duct in obstructive pancreatic disorders were studied histopathologically. Obstructive pancreatic disorders were observed in 25 out of 32 patients with pancreatic carcinoma. The main pancreatic duct was dilated in all 25 cases. Luminal conditions in the branches of the pancreatic duct were divided as follows: dilated, obstructed and unchanged. The dilated duct was found in all 25 cases and showed mainly cystic dilatation with flat epithelia. The obstructed duct was found in 10 cases and revealed granulation tissue in the lumen, disappearance of epithelia and increase in the number of elastic fibers in the periductal space. The pancreatic tissue distal to the tumor frequently showed isolated islets of Langerhans with elastosis. Morphogenesis of elastosis was interpreted as follows: during the process of shortening or disappearance of the duct, elastic fibers increased in number and remained in the fibrous tissue. Hence, the elastosis was considered to be a remnant in which the pancreatic duct had once existed. Therefore, the branches of the pancreatic duct in obstructive pancreatic disorder were classified into four types as follows: dilated, obstructed, remnant and unchanged.