Clinicopathologic features of poorly differentiated hepatocellular carcinoma.

Clinicopathologic features of poorly differentiated hepatocellular carcinoma (HCC) have not been elucidated. The purpose of this study was to clarify the characteristics of poorly differentiated HCC in hepatectomized patients. From 1986 to 2001, 354 HCC patients underwent curative hepatectomy in our institution and were prospectively followed. Histological examinations revealed 43 well-differentiated HCC tumors, 273 moderately differentiated HCC tumors, and 38 poorly differentiated HCC tumors. Clinicopathologic factors and outcomes after hepatectomy were compared statistically. Only serum alpha-fetoprotein level was significantly different in the poorly differentiated HCC group from that in the moderately differentiated HCC group preoperatively (P=0.0001). Although there were no significant differences between overall survival rates or between disease-free survival rates in the three groups, distant metastasis within 2 years after hepatectomy occurred more frequently in the poorly differentiated HCC group (21%) than in the well-differentiated HCC group (2%) (P=0.011) or moderately differentiated HCC group (8%) (P=0.018). Distant metastasis occurred in about 40% of patients in the poorly differentiated HCC group with tumor size greater than 3 cm. Poorly differentiated HCC tumors larger than 3 cm are already of advanced stage representing distant metastasis in the early period after hepatectomy.