[Identification the invasion range of hepatocellular carcinoma by contrast-enhanced ultrasound]

To study the histopathologic characteristics of the enlarged enhancement area of hepatocellular carcinoma (HCC) at contrast-enhanced ultrasound (CEUS) during the arterial or portal phase and evaluate the value of CEUS in identifying the invasion range of HCC.

Fifty-two patients with fifty-two lesions confirmed as HCC pathologically (41 by surgery and 11 by needle biopsy) were included. The lesion size, margin and shape at fundamental ultrasonography (US) and CEUS were compared before surgery or needle biopsy. Lesions with a larger enhancement area and/or a more irregular shape during the arterial or portal phase at CEUS were classified as group A; lesions with unchanged size and shape were classified as group B. The tissues specimens of the tumor margin (peripheral tumor tissues) were obtained and the slides were stained with HE and CD34 immunohistochemistry, the histopathology and microvessels density (MVD) of group A and B were compared.

In group A, 75% (24/32 lesions) had vaguely demarcated margin at US compared with 40% (8/20 lesions) in Group B (P < 0.05). The largest average diameter of Group A was 6.1 +/- 2.9 cm compared with 4.4 +/- 2.1 cm in group B (P < 0.05). Of the 41 surgically resected HCC specimens, 88% of the 75 slides for the 25 lesions in Group A demonstrated cancer cells invasion in the peripheral tumor, much higher than the 56.3% (27/48 slides) of the 16 lesions in Group B (P < 0.001). The MVD in Group A by CD34 immunohistochemistry was significant higher than that in Group B (52.25 vs 36.82, P < 0.01).

The enlarged enhancement area of HCC at CEUS correlated with the sharpness of tumor margins. The cancer cells invasion and more microvessels generation in the enlarged enhancement area reflected the histopathologic characteristics of invasive growth pattern of HCC. CEUS is helpful in identifying the actual tumor size and invasion range, and might be helpful for HCC treatment.