Incidentally discovered hepatocellular carcinoma in explanted liver: clinical, histopathologic features and outcome

Incidental hepatocellular carcinomas (iHCCs) are tumors discovered on the explanted liver that were not present on imaging before transplantation. The natural history, histopathologic characteristics, and prognosis are not clearly defined.

We compared the characteristics of iHCC and previously known hepatocellular carcinoma (pkHCC) in patients who underwent liver transplantation from 1998 to 2012 in a retrospective study.

During this period a total of 675 patients were transplanted; 56 patients (9%) had pkHCC and 12 (2%) had iHCC. The sex and age distributions were similar. The median Model for End-Stage Liver Disease score in iHCC patients was 17.0 versus 13.0 in patients with pkHCC (P = .001). Thirty-three percent of iHCC patients had multiple tumors, and 25% had bilobar involvement. The median cumulative tumor size in iHCC was 1.8 cm, and 5.5 cm in pkHCC (P = .005). Incidence of microvascular invasion was not different (16.7% vs 38.9%; P = .191). American Joint Committee on Cancer T1 stage was found in 58.3% of patients with iHCC and in 22.2% of pkHCC patients. Patients with iHCC had 1-, 3-, and 5-year survivals, respectively, of 100%, 83% and 64%, compared with 80%, 66%, and 38% for patients with pkHCC (P = .138). None of the patients with iHCC had recurrence of HCC, whereas incidence of recurrence in pkHCC patients was 12.5%.

iHCC occurred in patients with more advanced liver disease. The cumulative tumor size of iHCC was smaller but one-third were multifocal. Survival was similar to patients with pkHCC, and recurrence was not noted in patients with iHCC.