Endoscopic ultrasonography in the diagnosis of pancreatic islet cell tumors.

To evaluate the diagnostic value of endoscopic ultrasonography (EUS) in small-sized pancreatic islet cell tumors, sonograms obtained by extracorporeal ultrasonography (US) and EUS were reviewed. EUS was superior to US in accurately determining localization and tumor delineation. A small-sized tumor was visualized as a hypoechoic mass with central echogenic portions. Margin was clear, and contour was smooth. Microcysts were seen in four cases, strong echoes in two, and lateral shadowing in four. From these findings, which reflect histopathologic changes in the tumor, we believe EUS with its high-resolution is useful in preoperative diagnosis of pancreatic islet cell tumors.