A 13-year-old male patient presented with pain in right hypochondrium for two months. There was no history of fever, jaundice or weight loss. On examination the child was afebrile. Liver function tests and blood picture was normal. Alpha- fetoprotein (AFP) level was 1.8 ng/ml. (within normal range).
Non-contrast computed tomography (CT) showed a heterogeneous hepatic mass lesion with few coarse calcifications. There was no hepatomegaly. On contrast study, the lesion showed heterogeneous enhancement. It measured 6.2x4.4x4.5 cm and was involving liver segments II, III and IV. Few small non-enhancing areas were seen within the lesion. Inferiorly, there was loss of fat planes with gall bladder. Biliary radicles in left lobe of liver were moderately dilated. Enhancing thrombus was seen at portal vein bifurcation extending into left portal vein - suggestive of a malignant thrombus. No metastasis was seen in the lungs and abdomen on cross sectional imaging. Biopsy showed large eosinophilic tumour cells with intratumoral fibrosis, suggestive of fibrolamellar carcinoma.
Fibrolamellar carcinoma (FLC) is a type of HCC that usually occurs in young adults or adolescents who do not have a preexisting hepatic disease. Symptoms can be non-specific like abdominal pain, weight loss or malaise. Unlike hepatoblastoma and HCC, serum levels of AFP are generally not elevated. Areas of haemorrhage and necrosis are more common in conventional HCC which usually occurs in background of a cirrhotic liver.  On ultrasound, it appears as a solitary, heterogeneous mass of mixed echogenicity. A hyperechoic central scar can be present and may show calcifications with posterior acoustic shadowing. On CT, the lesion appears hypodense compared to adjacent liver, often with a central scar with or without calcifications. The central scar usually does not enhance on post-contrast images. MR imaging shows FLC to be mildly hypointense to isointense on T1-weighted images and slightly hyperintense on T2-weighted images. If a scar is present, it appears hypointense on both T1- and T2-weighted images due to its fibrous nature, as opposed to the scar of Focal Nodular Hyperplasia (FNH), which is hyperintense on T2-weighted images. Another differentiating feature is that FNH usually appears as homogeneously enhancing lesion on arterial phase CT. The attenuation of focal nodular hyperplasia is like that of surrounding liver parenchyma on portal venous and delayed phases. Calcification is more common in fibrolamellar hepatocellular carcinoma, though rare in FNH.  Mutations involving α-fetoprotein, TP53, β -catenin, and survivin are not found in fibrolamellar HCC, whereas these are commonly seen in conventional HCC. Portal vein thrombosis and biliary obstruction, as demonstrated in this case are rare findings in FLC.  Studies have shown that the presence of hypo-intensity of FLCs in hepatobiliary phase imaging compared with surrounding normal liver, highlights the role of gadoxetic acid-enhanced liver MRI for non-invasive diagnosis of FLC and its importance in the diagnosis of uncertain liver lesions.  Resectability is the most important prognostic factor affecting the outcome of fibrolamellar carcinoma with the median five-year survival rate for patients with a surgically removable fibrolamellar hepatocellular carcinoma being nearly 76%. FLC overall has a better prognosis than conventional HCC as surrounding liver is normal. Other favourable prognostic factors include lack of lymph node metastatic disease, lack of vascular invasion and negative excision margins.  Hepatic adenomas are more common in women and show variable imaging findings, often with areas of haemorrhage and necrosis in larger lesions. Written informed patient consent for publication has been obtained.
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