Multiple paraganglioneuromas.

We report multiple paraganglioneuromas which occurred in a 40-year-old-man. Thirty-two tumours with similar histological appearance have been reported previously and most of them showed a striking predilection to occur in the second portion of the duodenum. In this case, three masses were detected; one was located in the periampullary region of duodenum with a polypoid appearance, the others were well defined masses in peri-pancreatic tissue adjacent to large vessels. Histology revealed two cellular components, epithelioid cells with NSE immunoreactivity and S-100 protein containing spindle-shaped cells. Moreover, on electron microscopical examination, three different epithelioid cell types were seen. Type I was a figure differentiating to ganglion cells, type II to paraganglion cells, type III was a hybrid form of ganglion and paraganglion cells. Paraganglioneuroma revealed the histopathology of ganglioneuroma, paraganglioma and also a mixed appearance. In this respect the tumour may be considered to originate in undifferentiated neural crest cells and develop organoid differentiation.