HEPATOBLASTOMA HEPATOCELLULAR CARCINOMA

Hepatoblastoma and hepatocellular carcinoma (HCC)
Primary malignant tumours of the liver are comparatively rare in children and frequently present as a large abdominal mass. Large hepatic tumours may present acutely as a result of haemorrhage. Hepatoblastoma is the commonest primary liver malignancy in childhood, generally occurring in children under 3 years of age, and may be associated with predisposing conditions such as Beckwith–Wiedemann syndrome and children infected with HIV. HCC is more usually associated with chronic liver disease and tends to develop during the later stage of disease with peak incidences of 4–5 years and 12–14 years. Both tumours are associated with increased levels of serum alpha-fetoprotein.

On ultrasound, these tumours appear solid, heterogeneous and are often large and poorly demarcated from the adjacent liver parenchyma. Areas of necrosis or haemorrhage may be identified in the mass. Occasionally they may be multifocal. Although the two types of tumour are not distinguishable on ultrasound, the clinical history may give a clue and ultrasound-guided biopsy can be used to obtain a histological diagnosis.

Ultrasound is useful in identifying the extent of the tumour and, when combined with colour flow Doppler imaging, adjacent vascular invasion can be evaluated. CT or MRI complements the ultrasound findings and is essential for staging and assessment of suitability for resection or transplantation.

Chemotherapy may be used to shrink the tumour prior to surgery. Rhabdomyosarcoma is a rare tumour which may originate in the biliary ducts, causing biliary dilatation. It is indistinguishable from other liver tumours on ultrasound. Rhabdomyosarcoma originates from muscle cells and is the commonest type of soft-tissue sarcoma seen in childhood, with a peak incidence before 5 years of age. It occurs in various sites throughout the body.