So-called "papillary and cystic neoplasm of the pancreas." An immunohistochemical and ultrastructural study.

A case of so-called "papillary and cystic neoplasm of the pancreas" (PCNP) was reported and investigated immunohistochemically and ultrastructurally. A tumor of the pancreatic head in a 21-year-old female was curatively resected. The tumor was cystic and histologically consisted of uniform cells in papillary and solid structure. Although there was no immunoreactivity for pancreaticogut hormones or secretory products of the pancreas in the tumor cells, most of the tumor cells were diffusely immunoreactive for neuron-specific enolase (NSE). Some neurosecretory granules were detected in the tumor cells ultrastructurally. Both facts suggested endocrine cell character of the tumor. Certain cases of PCNP might show a differentiation to endocrine cells.