Tissue diagnosis of hepatocellular carcinoma

The current American Association for the Study of Liver Diseases (AASLD) guideline provides strategies for achieving the diagnosis of hepatocellular carcinoma (HCC) based on the size of liver nodules seen on surveillance imaging. For lesions less than 1 cm in size, follow-up surveillance imaging is recommended. Lesions larger than 2 cm require typical radiological hallmark on dynamic imaging. Lesions of 1-2 cm in size require typical imaging features including intense uptake of contrast during arterial phases followed by decreased enhancement during portal venous phases on at least 2 imaging modalities. In cases of atypical radiological features of the suspected lesion, tissue diagnosis either by fine needle aspiration or biopsy should be obtained. Although fine needle aspiration could give a smaller risk of seeding than biopsy, biopsy has been preferred over cytology. Percutaneous biopsy of HCC carries a potential risk of tumor seeding along the needle tract. However the risk is low and there is no clear evidence of post transplant recurrence due to needle tract seeding. Histopathologic assessment can differentiate between premalignant lesions such as dysplastic nodules and early HCC. Atypical variants of HCC can be recognized morphologically which may have associated prognostic value.