Liver transplantation and incidentally found hepatocellular carcinoma in liver explants: need for a new definition?

"Incidentally" identified hepatocellular carcinoma (iHCC) in liver explants after liver transplantation (LTx) is a frequently reported finding, which is characterized with a good prognosis. The purpose of this study was to evaluate the outcome of patients with these tumors in our series and in literature reports, and to compare their prognosis to that of HCC diagnosed preoperatively.

From April 1998 to December 2003, 432 patients underwent deceased-donor LTx at our center for nonmalignant indications. An additional 31 patients with a preoperative known HCC (pkHCC) received deceased-donor grafts. A literature search was performed intending to estimate the incidence of iHCC in liver explants and the outcome after LTx.

iHCC was found in 5 of the 432 patients. All five patients are currently alive without evidence of tumor recurrence after a median follow-up of 43 months. On the other hand, in the group of the 31 patients with pkHCC, 22 of them are at the moment alive in a median follow-up of 28 months. When comparing the two groups, no difference in survival could be found (P=0.1419 in log-rank test). Literature reports of 705 instances with iHCC over the past 20 years showed a statistical "better survival" in only 24 cases.

Literature reports showed a remarkable "deviation" of the expected tumor characteristics for the iHCC. Obviously, this is because of a widely characterization of iHCC, including also tumors which are rather undetected HCC during the waiting time to LTx. A more precise definition for the iHCC is needed.