Due to its non-specific symptomatology, diagnosis of hepatoma requires a high index of suspicion. The actual detection of hepatoma relies on combination of identifying common risk factors, serum tumor marker (alpha-fetoprotein) and the characteristic features of the tumor on radiologic imagings.
In endemic countries, the incidence of chronic HBV infection among patients with hepatoma can be as high as 90%. 70-80% of hepatoma has elevated serum alpha-fetoprotein. Alpha-fetoprotein level of more than 200ng/ml in the present of a solid space-occupying lesion in the liver is highly suggestive of a hepatoma.
Ultrasound scan is a very good screening tool for mass lesion in the liver in high risk patient. It is inexpensive, non invasive and readily available. However, it is operator dependent and lacks ability to provide a topographic picture that is needed in planning surgical intervention.
Contrast enhanced triphasic computerized tomography scan (CT scan) can provide high quality images of the liver and the tumor within it. Hepatoma is typically a hypervascular solid tumor with/without a clear capsule in the background of liver cirrhosis. The tendency of the tumor to invade portal veins and hepatic veins can also be clearing see on the CT scan. The added advantage of CT images is ability in studying the adjacent organs at the same time.
Magnetic resonance imaging (MRI) is a newer imaging technology that does not involve ionizing radiation. Its accuracy in detecting hepatoma is similar to CT scan but the cost is higher.
Characterizing small tumors (those <2cm) can be difficult on CT scan or MRI especially when the tumor marker is not elevated to diagnostic level. In such cases, short of doing a biopsy of the tumor, lipoidol CT scan may add confidence to the diagnosis of hepatoma. This works on the principal that hepatoma retains lipoidol (an oil based contrast) after injection through hepatic arteriography. A non-contrast enhanced plain CT scan is done 10 days to 2 weeks later, the retained lipoidol in the heptoma will light up brightly on the background of non-enhanced uninvolved liver parenchyma.
Hepatic artery angiography may also demonstrate the characteristic tumour blush of hepatoma.
In majority of patients, the diagnosis of hepatoma can be reached confidently with the combination of positive HBV or HCV viral serology, raised alph-fetoprotein and a CT scan showing a characteristic space-occupying lesion in the liver. Biopsy of the tumor is usually not necessary prior to surgical resection. Biopsy of the tumor is needed when the radiologic features of lesions are atypical; especially when the serology and tumor markers are not also supportive of the diagnosis; in patient whose tumor is technically unresectable or those who are deemed not suitable for operation due to other reasons.
Biopsy of the tumor can be done percutaneously under ultrasound or CT guidance; or laparoscopically (with keyhole operation). Core biopsy has better yield than fine needle aspiration but is associated with small risk of tumor bleeding and seeding along needle tract.