Extrahepatic tumor deposits misdiagnosed as intrahepatic metastases.

Focal hepatic lesions seen on roentgenologic evaluation of the liver in patients with cancer are usually assumed to be caused by parenchymal metastases. In this report, liver imaging tests showed six patients with filling defects caused by peritoneal carcinoma indenting the liver parenchyma. Extrahepatic tumor deposits were misdiagnosed in all but one of these cases. The roentgenographic characteristics that can assist in the differentiation of intrahepatic and extrahepatic metastases are a lens-shaped defect, a defect adjacent to the hemidiaphragm, and a halo around the liver suggesting peritoneal carcinomatosis. A high index of suspicion for extra-hepatic tumor masses causing intrahepatic filling defects may help prevent unnecessary exploratory surgery for treatment of hepatic metastases. Angiography may occasionally be helpful in distinguishing intrahepatic from extrahepatic disease.