Duodenal gangliocytic paraganglioma. An immunohistochemical and ultrastructural study and a hypothesis concerning its origin.

We report the immunohistochemical and ultrastructural features of three duodenal gangliocytic paragangliomas and compare them with duodenal carcinoid, extra-adrenal paraganglioma, pheochromocytoma, and ganglioneuroma. The gangliocytic paraganglioma is characterized by polygonal or columnar epithelial cells, ganglion cells, and spindle cells. The epithelial cells stained for neurofilament, neuron-specific enolase, pancreatic polypeptide, and somatostatin in three cases; leu-enkephalin, molluskan cardioexcitatory peptide, and vasoactive intestinal peptide in two; and glucagon and insulin in one case each. The ganglion cells were positive for leu-enkephalin, neurofilament, neuron-specific enolase, pancreatic polypeptide, and somatostatin in three cases, and glucagon in one. The spindle cells stained for neurofilament, neuron-specific enolase, and S-100 protein. Although there was some overlap in immunoreactivity between the gangliocytic paraganglioma and the other tumors examined, our data indicate that the gangliocytic paraganglioma is a distinctive lesion. We propose that it is a hyperplastic or neoplastic proliferation of 1) endodermally derived epithelial cells originating from the ventral primordium of the pancreas, 2) neuroectodermal ganglion cells, and 3) neuroectodermal spindle cells (Schwann cells).