Endoscopic ultrasonographic criteria of vascular invasion by potentially resectable pancreatic tumors.

Endoscopic ultrasonography was used to examine 38 patients with a pancreatic neoplasm (mean size, 2.8 cm; range, 1 to 5 cm). Three EUS signs appear to be reliable criteria for the identification of tumor invasion of major veins forming the portal confluence: (1) peri-pancreatic venous collaterals in the area of a mass that obliterates the normal anatomic location of a major portal confluence vessel; (2) tumor within the vessel lumen; and (3) abnormal vessel contour with loss of the vessel-parenchymal sonographic interface. At least one of these signs was present in each of the 21 patients with vascular invasion; none of them was present in the 17 patients without vascular invasion. Findings were confirmed by laparotomy plus biopsy (33 patients), autopsy (1 patient), or angiography plus biopsy (4 patients). Arterial involvement was identified by alteration of vessel course and caliber. All 7 patients with arterial involvement also had venous involvement. These signs provide reliable criteria for endoscopic ultrasonographic definition of unresectable tumors in patients with a pancreatic neoplasm that appears to be resectable on standard radiologic tests.