Focal nodular hyperplasia and liver cell adenoma: radiologic and pathologic differentiation

Abstract

Diagnosis of either focal nodular hyperplasia or liver cell adenoma presents problems to the radiologists and pathologists mainly because of inconsistent pathologic classification of these lesions. This paper presents the characteristic features of focal nodular hyperplasia and liver cell adenoma and outlines the radiologic manifestations for differentiation. Focal nodular hyperplasia has a generally innocuous natural history while liver cell adenoma has potential for life-threatening hemorrhage. 2 surgical pathologists independently reviewed case files from the surgical pathology laboratory of Columbia University and all literature reports of benign hepatic neoplasms from 1940-1976. 38 reported cases of benign liver tumors were identified in which there was an unequivocal pathologic diagnosis and adequate radiologic data for analysis. There were 26 cases of focal nodular hyperplasia and 12 of liver cell adenoma. 8 local cases with angiographic and radionuclide scan data were correlated with the pathologic diagnosis. Radiologic signs for hyperplasia include a hypervascular mass with tightly tortuous arteries and a septated blush on the capillary phase of angiography. 1/3 of these lesions captured sulfur colloid on radionuclide scans indicating Kupfer cell activity. Combined with uptake of radioactive colloid in the mass the angiographic findings are virtually diagnostic. In contrast angiographic findings for liver cell adenoma ranged from completely avascular to hypervascular with or without accompanying adjacent hematoma. All cases of adenoma showed clear defects on liver scan reflecting total lack of Kupfer cells. Some cases will continue to present diagnostic problems for the radiologist and pathologist. Hypervascular lesions which lack the typical angiographic features of hyperplasia and do not capture sulfur colloid require excisional biopsy for proper management. However an unequivocal diagnosis of focal nodular hyperplasia requires a more conservative management because of its innocuous nature.