Carcinoid tumor of the pancreas with obstructive pancreatitis.

A case of primary pancreatic enterochromaffin cell (EC cell) carcinoid tumor in a 66-yr-old Japanese man is presented. The markedly dilated main pancreatic duct was noticed at the time of an incidental ultrasonogram during hospitalization for diabetes mellitus. Endoscopic retrograde pancreatography showed stenosis of the main pancreatic duct at the body of the pancreas and dilated pancreatic ducts distal to the obstruction. A distal pancreatectomy was performed, together with splenectomy. Macroscopically, the main pancreatic duct was compressed by a fibrous mass around the duct, and the pancreatic ducts distal to the tumor were markedly dilated. Histologically, the tumor was composed of uniform round cells, proliferating in small nests or trabeculae. The tumor cells were strongly positive with both Grimelius and Fontana-Masson stains. The immunohistochemical study disclosed the tumor cells to be positive for serotonin and chromogranin. This is a rare case of primary pancreatic EC cell carcinoid tumor with obstructive pancreatitis.