Differential Diagnosis Fat containing HCC Fatty metamophosis of HCC - 17% of small HCC, a/w decrease in the number of intratumoral arteries MR - hypervascularisation in the arterial phase, washout in portal/delayed phase - high SI on T1WI, SI drop on chemical shift images (Hm, intratumoral fat) - bulky tumor : capsule, mosaic perfusion Arterial Portal Delayed

Differential Diagnosis Fat containing HCC Fatty metamophosis of HCC - 17% of small HCC, a/w decrease in the number of intratumoral arteries MR - hypervascularisation in the arterial phase, washout in portal/delayed phase - high SI on T1WI, SI drop on chemical shift images (Hm, intratumoral fat) - bulky tumor : capsule, mosaic perfusion T2WI In-phase Out-of-phase

Differential Diagnosis Hepatic AML Non-homogeneous, variable high SI on T1WI/T2WI SI drop on fat-suppressed images Non-homogeneous early and persistence of enhancement Washout in the portal phase and delayed phase, no fibrous capsule Vessels are present in and around the tumor T2WI In-phase Out-of-phase

Differential Diagnosis Hepatic AML Non-homogeneous, variable high SI on T1WI/T2WI SI drop on fat-suppressed images Non-homogeneous early and persistence of enhancement Washout in the portal phase and delayed phase, no fibrous capsule Vessels are present in and around the tumor Arterial Portal Delayed

Hepatic AML Benign mesenchymal neoplasm Diagnosis Treatment Heterogeneous mixture of smooth muscle cells, thick-walled blood vessels, and mature adipose tissue Liver : 2nd m/c, asymptomatic Diagnosis Pathologic finding supported by immunohistochemical staining HMB-45 (+) : smooth muscle cell Treatment Asymptomatic : observation Abdominal pain, bleeding : surgical resection

Hepatic AML Radiographic findings Single or multiple, round or lobulated fat containing mass lesions Seen more commonly in the right hepatic lobe Presence of both fat and prominent vascularity, fat proportion 5-90% Hepatic AML has been misdiagnosed as HCC >50% frequency

Hepatic AML Radiographic findings US : hetero or homogenous echogenic/ heterogenous hypoechoic CT and MRI Presence of fatty component Marked inhomogenous early enhancement , delay washout On hepatobiliary phase : low SI Diffusion restriction d/t muscle and fat components FDG-PET Varying amounts of FDG uptake (hemorrhage, inflammatory response)

Hepatic AML DDx. with fat containing HCC Early venous return in the arterial or portal phase 73% of AML vs. 8% of HCC , portal vein or hepatic vein More prominent & ecstatic tumoral vs. connecting early draining vein Seen with smaller tumor size HCC : arterial branches that were connected to feeding artery Irregular tumor border with capsular formation 80% of HCC vs. 0.5% of AML

Hepatic AML DDx. with fat containing HCC Upstream bile duct dilatation, PV or HV involvement Necrosis, retraction of liver surface Without symptoms and risk factors for liver malignancy Chronic hepatitis, liver cirrhosis, alcohol abuse With normal serum tumor markers

Hepatic AML Hepatic AML European Journal of Radiology, 2010; 73: 601-606

Hepatic AML HCC European Journal of Radiology, 2010; 73: 601-606

Reference Case 1 AJR 2016;307:562-570 RadioGraphics 2005; 25:321-331 Diagnostic and Interventional Imaging 2015; 96: 201-211 European Journal of Radiology, 2010; 73: 601-606 Abdomen Imaging 2014; 39:323-333 Surgical Case Reports 2015;1:38 Surgical Case Reports 2015;1:11 Clinical and Molecular Hepatology 2012; 18: 330-335