Liver parenchyma at the site of hypodense parafissural pseudolesion contains increased collagen

To identify a histological substrate explaining the hypodense pseudolesion in the liver at the right side of the falciform ligament and the correlation with CT radiodensity. Tissue specimens were obtained from the right (pseudolesion) and left (control) side of the falciform ligament at the level of the left portal vein, in deceased adults during autopsy. Radiodensity was measured at the same locations at CT. Digital image analysis determined the amount of collagen and fat in histological sections, and the number of portal triads and central veins were counted. Glycogen content was visually assessed by the area percentage of the histological section. Specimens from 17 patients showed a 39% increase in collagen for the site of the pseudolesion compared to the contralateral side (p = 0.08). No significant differences were found for the amount of fat, glycogen, portal triads, or central veins. In one patient a pseudolesion was visible on CT, and this contained 52% more collagen than the control side. The pseudolesion at the right parafissural side in the liver contains more collagen compared to the control left side, while there is no difference in fat or glycogen content or number of portal and hepatic veins. Collagen may be the cause of the pseudolesion.