Papillary process of the caudate lobe of the liver: sonographic appearance

The papillary process of the caudate lobe of the liver may appear separate from the liver and thus mimic lymph nodes or a pancreatic mass. In order to evaluate the sonographic appearance of this anatomic structure, 400 male and female patients with a mean age of 50 years were studied prospectively by means of ultrasound. The papillary process appeared to be separate from the liver on transverse sonograms in 62 patients (15.5%) and had an egg shape with a maximal transverse diameter of 8-39 mm. In all 62 patients, the papillary process appeared above and in front of the common hepatic artery close to the portal vein and pancreatic isthmus. Enlarged papillary processes were more frequently seen in patients with chronic liver disease. Knowledge of the anatomy, sonographic pattern, and vascular relationships of the papillary process enable its correct identification.