IS Case 247: Recurrent hepatocellular carcinoma
Imaging Sciences URMC 2008
Publication Date: 2009-05-26
Non-contrast CT demonstrates a round area of markedly increased attenuation in the right lobe of the liver, corresponding to HCC post-chemoembolization. Arterial phase contrast enhanced CT at the same level demonstrates a crescent-shaped region of enhancing tissue adjacent to the zone of chemoembolization.
Recurrent hepatocellular carcinoma
Trans-arterial chemoembolization (TACE) of hepatocellular carcinoma is an established treatment modality for unresectable disease, improving 2-year survival compared to conservative therapy (57% vs 27%) . TACE has also been used as neoadjuvant therapy prior to "curative" surgery with good results. The role of TACE in downstaging unresectable disease is less well established. TACE exposes the tumor to high concentrations of chemotherapeutic agents while limiting systemic exposure and side effects. The rationale for TACE is that blood supply to hepatocellular carcinoma is almost exclusively arterial, while blood supply to normal hepatic tissue is predominantly via the portal system.
The infusion mixture consists of iodinated oil (ethiodol) and a chemotherapeutic agent (cisplatin) along with contrast and saline in a slow release emulsion. An embolic agent such as gelfoam is also used to decrease blood flow to the tumor. Iodinated oil remains in the embolized tumor tissue for a prolonged time period, increasing the time of exposure to the chemo agents and accounting for the high attenuation on post TACE CT scans (Fig. 1)
Post TACE CT can show several patterns of ethiodol accumulation. The greater the accumulation, the more effective was the treatment. Faint, patchy or incomplete accumulation implies residual tumor. Enhancing tissue within the region of embolized tissue also suggests residual tumor. Enhancing tissue along the margin of the embolized region, as in our case (Fig. 2), implies recurrent disease with tumor growth. HCC is a strongly angiogenic neoplasm. In our example, the tumor has recruited arterial blood supply from the right internal mammary artery (Fig. 3). While angiogenesis arising from other hepatic artery branches is not uncommon after TACE, recruitment of nonvisceral arteries, as in our case, is uncommon. The superior location of the tumor is an important factor.
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