Histopathological findings after ultraselective transcatheter arterial chemoembolization for hepatocellular carcinoma

To evaluate the histopathologic findings in the surgical specimen of hepatocelluar carcinoma after transcatheter arterial chemoembolization (TACE) at the most distal portion of the sub-subsegmental artery of the liver (ultraselective TACE). Histolopathologic findings from nine tumors with a mean diameter of 3.1 cm +/- 1.7 from patients who underwent hepatectomy after ultraselective TACE were evaluated, especially with regard to the relationship between peritumoral liver parenchymal necrosis and portal vein visualization during TACE. Portal vein visualization was classified into three grades by a spot digital radiograph obtained just after TACE: 0, no obvious portal vein visualization; 1, visualization of the portal vein adjacent to the tumor; and 2, visualization in the whole embolized area or extending into the surrounding non-embolized areas. Unenhanced computed tomography (CT) was obtained 1 week later and surgical resection was performed 37 +/- 6.3 days after ultraselective TACE. Portal vein visualization during TACE was classed as grade 1 in 5 tumors and grade 2 in 4. Histopathologically, complete tumor necrosis was observed in 7 tumors (77.8%). In 2 tumors (1 of grade 1, the other grade 2), a small viable portion or viable daughter nodule was seen. Macroscopic parenchymal necrosis adjacent to the tumor was observed in all 4 grade 2 tumors including gas-containing areas on CT obtained 1 week after TACE. Ultraselective TACE induces not only complete tumor necrosis but also peritumoral parenchymal necrosis, similar to that after radiofrequency ablation, when the portal veins are markedly visualized during the TACE procedure.