Liver neoplasms: diagnostic pitfalls in cross-sectional imaging.

The appearances of most common liver neoplasms at computed tomography (CT) and magnetic resonance (MR) imaging have been established. However, there are considerable overlaps in the appearances of various pathologic entities. Certain hepatic lesions, such as hepatic hemangioma, adenoma, focal nodular hyperplasia, intrahepatic cholangiocarcinoma, metastases, hepatocellular carcinoma, regenerative nodules, adenomatous hyperplastic nodules, abscess, and hepatocellular carcinoma treated with transcatheter arterial chemoembolization, can have unusual characteristics at CT and MR imaging that may lead to misinterpretation. Dynamic helical CT and double-phase multisection dynamic MR imaging techniques may be helpful in differentiating between these entities because hemodynamics of the lesion can be evaluated by obtaining both arterial-phase and delayed-phase images. It is important for radiologists to be aware of these uncommon appearances of liver neoplasms. Familiarity with these varied CT and MR imaging features will permit a more accurate diagnosis and aid in avoidance of a false diagnosis.