CT appearances of hepatic angiomyolipoma (HAML)

Objective: To study the imaging features of hepatic angiomyolipoma (HAML) on CT so as to improve the diagnostic accuracy. Methods: CT findings of 12 cases with pathologically-proved hepatic angiomyolipoma were retrospectively summarized and analyzed, additional thin slice scan was done on arterial phase and portal phase in 8 cases, multi-planar reconstruction (MPR), maximum intensity projection (MIP) and volume rendering technique (VR) were carried out in 5 cases. Results: Of the 12 patients, 10 were female. 7 lesions were located in right hepatic lobe, 5 were in left hepatic lobe, in which 2 lesions outgrew from hepatic lobe. 12 lesions appeared as hypo-density on precontrast CT scan. The first group consisted of 7 lesions with inhomogeneous density and fat density, which could be measured with CT values<-20HU. The soft tissue component of the 7 lesions were markedly and unevenly enhanced on arterial phase and continued on portal phase. Then the density reduced on parenchymal phase. The second group consisted of 5 lesions with homogeneous density. One lesions was fat density with CT values of -54HU without marked enhancement on contrast scanning. Most part of the other 4 lesions soft tissue density with markedly enhanced on arterial phase and continuously enhanced on portal phase, equidensity in 1 lesion and low density in the other 3 lesions on parenchymal phase. The central vascular structure could be seen in 5 lesions on arterial phase and/or portal phase, and one of that led into hepatic vein. Conclusion: Although the CT appearances of HAML showed with different components of the tumor, it will be helpful to improve the diagnostic accuracy before surgery if the characteristic CT appearances of HAML were accurately grasped. (authors)