Comparative Study of Focal Nodular Hyperplasia:Radiologic and Pathologic Features

Objective To explore the pathological and imaging characteristics of focal nodular hyperplasia(FNH) of liver.Methods 17 cases of FNH proven pathologically underwent triphase spiral CT scan,of them,10 cases underwent fast MR imaging.The pathological andimaging features were comparatively analysed.Results All lesions were a solitary globular or lobulated mass,the majority of cases wasapproximately 2~5 cm in diameter.On plain CT and MRI,FNH was classically seen as a solitary,homogeneous and slightly hypoattenuating or isoattenuating area in comparison with normal liver,slightly hyper-or isointense on T_2WI,intense homogeneous enhancement during the arterial phase of enhanced imaging,and hyperattenuating in 12 cases,hypoattenuating or isoattenuating in 6 cases in comparison with normal liver during venous and delayed phase.The central scar was showed in 11 cases during delayed phase and 8 cases showed delayed enhancement,4 cases had pseudocapsular like enhancement in delayed images.In histology,17 cases of FNH were well limited but nonencapsulated,the hyperplastic parenchyma of the liver was subdivided into small nodules surrounded by the fibrous septa,there was a central scar composedof fibrous connective tissue and malformed vessels of various caliber.Conclusion The typical FNH can be easily diagnosed,while theatypical cases should be differentiated from hepatocelluar adenoma,hepatocellular carcinoma and hemangiomas.