[Sonographic diagnosis of nonmalignant extrahepatic portal venous obstruction--incidence and background].

We diagnosed nine cases of nonmalignant extrahepatic portal venous obstruction on ultrasonography at Kitakyushu Municipal Kokura Hospital between 1983 and 1989. Among 40544 cases of routine abdominal ultrasound study, nine cases of nonmalignant extrahepatic portal venous obstruction were found. The sonographic feature of "cavernous transformation" of the portal vein was noted at an incidence of about 1/2000. We classified these nine cases into three groups according to past history. Four cases underwent abdominal surgery. (Two had two operations). Three had abdominal inflammation or trauma, and two had no significant history, although one had taken oral contraceptive pills intermittently during the last ten years.