Comparison of CT enhancement patterns and histologic features in hepatocellular carcinoma up to 2 cm: assessment of malignant potential with claudin-10 immunohistochemistry.

The purpose of this study was to compare features of computed tomography (CT) and histologic features of hepatocellular carcinoma (HCC) of up to 2 cm in diameter with the immunohistochemical staining pattern of claudin-10, a recently identified prognostic factor for resected HCC. Twelve cases of resected HCC of up to 2 cm in diameter were assessed retrospectively. Preoperative dynamic CT was reviewed, and three enhancement patterns were identified. Type I (n=6) was defined as a pattern of hyperenhancement throughout the tumor in early-phase CT, decreasing to hypoenhancement in late-phase CT (high-low), a finding characteristic of HCC. Type II tumors (n=2) appeared as an area of hyperenhancement in early-phase CT, and an area of hyperenhancement in late-phase CT (low-high). Histologically, type II tumors were considered unusual types, and included combined hepatocellular-cholangiocarcinoma and scirrhous HCC. In type III tumors (n=4), high-low, low-high and low-low components were observed. Type III tumors showed multinodular-type morphology and comprised both moderately and poorly differentiated HCC with marked necrosis and fibrosis. Each nodule was divided by fibrous septa. In three of the four type III cases, recurrence occurred within 6 months after resection. Immunohistochemistry of claudin-10 showed positivity in five of the 12 cases, including four type III cases. Results of this study suggest that type III tumors have greater malignant potential than the other tumor types.