Imaging Diagnosis :
Study reveals an
isodense mass lesion, with homogenous enhancement on contrast administration.
Because conventional HCC also may contain lipid or fat and may resemble adenoma at MR imaging, it can be difficult to make this distinction with imaging alone. Other criteria, such as interval growth or elevated serum -fetoprotein levels, favor a diagnosis of HCC. An adenoma can undergo malignant change to HCC even after years of a stable appearance.
Adenoma and FNH have several features in common, which include their tendency to occur in young women, and may share certain CT features. FNH does not undergo malignant degeneration, nor is it likely to bleed. FNH may demonstrate small central and septal arteries, along with early draining veins. In distinguishing between FNH and adenoma, MR imaging may be useful. MR imaging is even more sensitive than CT in depicting the characteristic central scar of FNH.
Multiphasic, helical CT can demonstrate findings characteristic of hepatic adenoma. These include the presence of a single mass or multiple masses that may contain areas of fat or hemorrhage but that are otherwise nearly isoattenuating to normal liver on nonenhanced, PVP, and delayed scans. The lesions are moderately hyperattenuating to liver on the HAP images and enhance nearly homogeneously. They are sharply marginated and nonlobulated. Other features such as tumor capsule, early draining veins, and calcification are less common and overlap findings encountered in other hepatic masses. Atypical features such as heterogeneous enhancement may require additional imaging, such as MR imaging, or may require biopsy or even surgical resection in some cases to exclude a malignant neoplasm.
Tomoaki Ichikawa, Michael P. Federle, Luigi Grazioli, and Michael Nalesnik
Dr. Sandeep Nyayanirgune, Mumbai