Presentation
Right sided abdominal pain since one month
Patient Data
Liver is enlarged and shows diffuse steatosis. Multiple relatively hyperdense and differential enhancement areas are seen in both the lobes showing relative arterial enhancement with no significant washout on later phases, distributed predominantly in the subcapsular region. Tortuous hepatic artery coursing through segment 2 likely due to arterioportal shunting. The porta hepatis is normal. No intrahepatic biliary dilation or common bile duct dilatation. Left lower lobe posterior segment atelectasis with calcific foci within and few surrounding linear bands. No obvious lesion appreciable in the proximal bronchi.
Histopathology of the liver lesion showed no evidence of malignancy.
Endobronchial ultrasound guided biopsy showed reactive lymphoid cells with no evidence of malignancy.
Case Discussion
Hepatic steatosis is a common radiologic finding with obesity, alcohol abuse, metabolic and hereditary disorders and viral hepatitis to be the considered among the common underlying conditions 1. Focal fatty infiltration and focal fat sparing areas in the liver may occasionally show a multinodular appearance on imaging, mimicking benign and malignant liver lesions with the correct differentiation being more important in patients with known cancer undergoing chemotherapy as these lesions may simulate liver metastases 1,2. Focal fat deposition is often seen in patients clinical undergoing chemotherapy 1.
It is proposed that the focal areas of fatty deposition or sparing are associated with vascular supply to the liver other than the hepatic artery and the portal vein. The intrahepatic portal branches may communicate with aberrant veins that enter the liver separately from the portal vein; this could result in focal perfusional variations and subsequent metabolic changes in the liver parenchyma. The pancreas head is drained through the parabiliary venous system, which may lead to increased insulin delivery concentrations, which may then cause metabolic alterations in the liver parenchyma 2.
Focal fatty sparing usually occurs near the gallbladder fossa and porta hepatis on a background of diffuse fatty infiltration. Focal fatty sparing is seen as an area of decreased echogenicity on ultrasonography and is seen as a hyper dense area on CT. Focal fat sparing lesions are clearly seen only on opposed phase MRI. Although true primary or secondary tumor of the liver can also be better appreciated on opposed-phase imaging in a diffusely fatty liver, they show increased signal on T2W images or show altered vascularity in comparison to the rest of the liver parenchyma on contrast enhanced MRI. Biopsy is the definitive test for the diagnosis 2-4.
In our case, the possibility of fat sparing was raised, and MRI imaging was suggested for further evaluation. However, the patient opted to undergo a guided biopsy of the liver lesion, which showed no evidence of malignancy. The patient also underwent an endobronchial ultrasound-guided biopsy for the left lower lung segmental collapse, which showed reactive lymphoid cells with no evidence of malignancy.
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