Clinicopathologic features of poorly differentiated hepatocellular carcinoma

Background and Objectives: 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. Methods: 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. Results: 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. Conclusions: Poorly differentiated HCC tumors larger than 3 cm are already of advanced stage representing distant metastasis in the early period after hepatectomy.