[Pathological study of extracorporeally ablated hepatocellular carcinoma with high-intensity focused ultrasound]

To investigate the pathological changes of hepatocellular carcinoma (HCC) after extracorporeal ablation with high-intensity focused ultrasound (HIFU).

A total of 56 patients with HCC was treated with HIFU. Of the 56 patients treated, 6 underwent surgical resection of the tumor 5 to 18 days following HIFU treatment The resected specimens were examined under light and electron microscope.

Light microscope examination showed clear boundary between the treated and untreated area. Outside of the boundary the hepatic parenchyma was almost normal. In the treated area, all tumor cells appeared irreversibly dead in the forms of nuclear pyknosis, debris, and dissolution. The blood sinusoids were collapsing with endothelial cell damage. Granulation tissue was formed with the presence of immature fibroblasts and new capillaries in the boundary region between treated and untreated area. Eighteen days after HIFU treatment, the ultrasound damaged area was partially replaced by the proliferative repair tissue. Electronic microscopic examination showed the distorted tumor cells with severe destruction of cell organelles and nuclei. The cytoplasm was irregularly vesiculated, and the membranes of the organelles were broken. Cell membrane and nuclear membrane disintegration, as well as nucleus disruption were generally observed.

Extracorporeal treatment of HCC with HIFU proved safe, effective, and feasible. This modality could potentially provide a new and noninvasive therapy for HCC.