Tumor cell proliferation of hepatocellular carcinoma, with special reference to ultrasonographic findings and arterial vascularity by US angiography

Introduction: To determine the clinical significance of tumor-cell proliferation in hepatocellular carcinoma (HCC), we investigated the relationship between tumor-cell proliferation evaluated by Ki-67 labeling index and ultrasonographic findings and degree of arterial vascularity evaluated by US angiography inpatients with HCC. Methods: HCC cells from 70 histologically confirmed HCC nodules obtained at biopsy of 64 patients were immunohistochemically studied for Ki-67 labeling index. We compared such corresponding ultrasonographic findings as tumor diameter, halo, and internal echo pattern, and the degree of arterial vascularity on US angiography. Arterial vascularity was then classified into three grades based on the findings of digital subtraction angiography (DSA) and US angiography. Results: Nodule diameter greater than 3 cm, presence of halo, or presence of internal echo with a mosaic pattern, alone or in combination, indicated enhanced proliferation of tumor cells. Although enhanced proliferation of tumor cells was seen in nodules with a strong arterial vascularity that could be detected by DSA, proliferation was not enhanced in nodules with a weak arterial vascularity that could be detected only by US angiography. Conclusion: HCC with weak arterial vascularity detectable only by US angiography may show a lower grade of biological malignancy, suggesting that prognosis is improved by early diagnosis and treatment of these lesions.