Sonographic differentiation of extra- and intrahepatic masses

The sonographic features in the evaluation and differentiation of extra- and intrahepatic masses were assessed in two groups of patients. These signs included discontinuity of the liver capsule, internal invagination or external bulging of the liver capsule, formation of a retroperitoneal fat wedge, displacement of the intrahepatic portal vessels or hepatic veins, shift of the inferior vena cava, and displacement of the right kidney. Evaluation of the results in 25 patients in whom the mass was intrahepatic and in 33 with an extrahepatic mass indicates that internal invagination of liver capsule (81.8%), its discontinuity (33.3%), formation of triangular fat wedge (75.7%), shift of the inferior vena cava anteromedially (36.3%), and anterior displacement of right kidney (28.1%) are the signs most frequently observed in extrahepatic masses. The characteristic features of the intrahepatic masses were displacement of hepatic vascular radicles (84%), external bulging of the liver capsule (56%), and posterior shift of the inferior vena cava (32%). The evaluation of masses in the right upper abdomen according to these criteria gives an accurate definition of their anatomic origin. However, masses exceeding 10 cm in diameter may present diagnostic problems.