Paediatric Imaging

Carcinoma, hepatocellular

primary liver tumour arising in mature hepatocytes. It is the second commonest primary hepatic tumour in children, presenting in the second decade and uncommon, compared with hepatoblastoma, which occurs before the age of 5 years. Clinical presentation is with upper abdominal pain and a palpable right upper quadrant mass. The tumour is often multifocal and locally invasive at presentation. Fibrolamellar hepatocellular carcinoma occurring in older children and adults is not associated with pre-existing cirrhosis and unlike other forms of hepatocellular carcinoma, does not produce alphafetoproteins. It may have a more favourable prognosis.

Imaging

The imaging appearance of hepatocellular carcinoma is that of an upper abdominal mass, 5% of which contain calcification. The tumour on ultrasound is of mixed echodensity. Hepatic vein invasion or anatomy must be identified to assess suitability for resection. This is best done with MRI. Gadolinium enhancement is required. Calcification, which may only be seen on CT or ultrasound, is rarely present in hepatocellular carcinoma while it is seen in 40% of hepatoblastomas. Otherwise the lesions are very similar with a low signal on T1- and high signal on T2-weighted images, with signal void if the calcification is large enough. There is tumour enhancement except where there is necrosis or haemorrhage. Gadolinium enhancement improves evaluation of the tumour size since on STIR sequences it will distinguish tumour from oedema. Chest CT should be carried out to detect any pulmonary metastases. Hepatocellular carcinoma is associated with hepatitis B infection and cirrhosis, tyrosinaemia, Wilson disease, cystinosis, and type I glycogen storage disease.

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