Hepatocellular carcinoma with intra-atrial tumor growth. A clinicopathologic study of 18 autopsy cases.

We studied the features of 18 cases of hepatocellular carcinoma (HCC) with prominent intra-atrial tumor growth that were seen among 439 autopsy cases of HCC. Diuretic-resistant, marked edema in the lower extremities and marked venous dilatation in the abdominal wall were observed in 14 cases (77.7%) and five cases (27.7%), respectively. Consistent tachycardia was seen in three cases. Macroscopically, most of the cases showed an infiltrative or mixed (infiltrative and nodular) growth pattern. A continuous tumor thrombus involving the right atrium, the IVC, and the hepatic vein was seen in 15 cases; a tumor that involved the right atrium alone was present in three cases. In five cases, the tumor bolus crossed the tricuspid valve and entered the ventricle.