The papillary and solid neoplasm of the pancreas: a report of two cases with electron microscopy, one containing neurosecretory granules.

Two pancreatic tumors occurred in young women without detected functional symptoms. They had similar gross and histologic features and appeared to be of low grade malignancy. Case 1 was a typical example of the recently described entity referred to as papillary and solid neoplasm of the pancreas. Electron microscopic findings in this case indicated a duct cell origin, similar to previously reported cases. Case 2, also ultrastructurally similar, is unique in that it contained neurosecretory granules. Since considerable evidence indicated that cells of small pancreatic ducts give rise to islet cells, case 2 suggests that some tumors of ductal origin recapitulate the embryogenesis of the pancreatic islets and, therefore, may contain neurosecretory granules without showing the classic morphology of the more common pancreatic endocrine tumors.