The Influence of Histological Differentiation Grade on the Outcome of Liver Resection for Hepatocellular Carcinomas 2 cm or Smaller in Size.

Background: Small hepatocellular carcinomas (HCC) with poorly differentiated components (PDC) are reportedly at risk of dissemination and needle tract seeding after percutaneous radiofrequency ablation, although it is the preferred treatment for HCC ≤ 2 cm because of the low rate of vascular invasion. On the other hand, the clinical outcomes after hepatectomy for these tumors are still unclear because of their rarity. Methods: A total of 233 cases of solitary HCC ≤ 2 cm were retrospectively reviewed and divided into two groups according to the presence of PDC: 199 without PDC (NP-HCCs) and 34 with PDC (P-HCCs). The clinicopathological characteristics and prognosis were compared. Results: A comparison of clinicopathological characteristics showed that the elevation of the tumor markers alpha-fetoprotein (AFP) (>20 ng/mL) and des-gamma-carboxyprothrombin (DCP) (>40 AU/L) was significantly frequent in P-HCCs. The 3- and 5-year recurrence-free survival rates for P-HCCS were 39 and 29 %, respectively, which were significantly worse than those for NP-HCCs (64 and 50 %, respectively) ( p < 0.01). Initial recurrence of P-HCCs was significantly more frequent, as well as extrahepatic recurrence and advanced recurrence in the early period after the operation. Recurrences with tumor dissemination were observed in 15 % of P-HCCs and 4 % of NP-HCCs ( p = 0.03). Conclusion: PDC is present in 15 % of HCC < 2 cm and should be suspected when the both tumor markers are elevated. Moreover, significantly worse post-hepatectomy outcomes such as early advanced recurrence or recurrence with dissemination should be taken into account if PDC is present even in HCCs ≤ 2 cm. [ABSTRACT FROM AUTHOR]