Abstract
A76-year-old woman was admitted to our hospital because of liver dysfuntion andcholedocho-pancreatic duct dilatation. Abdominal US showed a choledochal stone and a solidmass, which revealed strong blood signal by means of color Doppler imaging, in the permampullary region. The choledochal stone was extracted endoscopically after sphincterotomy.Biopsy from the surface of the exposed mass was performed and histology revealed neuroendocrine tumor. Pyrolus-preserving pancreaticoduodenectomy was performed. The tumorproduced only pancreatic polypeptide which was confirmed by the imxnunohistochemical technique. The tumor was extended along the main pancreatic duct to the ampulla of Vater, whichmay have caused the formation of choledochal stone. The location of tumor suggested that thetumor arised from endocrine stem cell in the pancreatic duct epithelium. PPoma is extremelyrare, and only five cases have been reported previously in Japan.
