Contribution of imaging techniques to the differential diagnosis of adenoma and focal nodular hyperplasia of the liver.

The most common hepatocyte tumors are focal nodular hyperplasia and adenoma. Both are benign and predominantly affect women. Hepatocyte adenomas may be directly related to oral contraceptive use. The diagnosis of focal nodular hyperplasia currently rests on color Doppler ultrasonography and on magnetic resonance imaging with dynamic sequences and intravenous gadolinium to demonstrate the central scar. No treatment is needed if the imaging study findings are characteristic, which is the case in about 70 % of patients. Adenomas can contain fat and structures that bleed, which call make them difficult to differentiate from primary liver cancer. There are no specific imaging study findings for adenoma. All suspected adenomas should be removed surgically, unless there is a major contraindication. Follow-up is in order after the procedure, and oral contraceptive use should be stopped.