Confirmation of the donor origin of de novo hepatocellular carcinoma after liver transplant using microsatellite analysis.

Objective: The recurrence of hepatocellular carcinoma (HCC) after liver transplant (LT) occurs in 10% to 15% of cases, but de novo HCC arising in an allograft is a rare occurrence. The aim of this study was to determine the origin of post-LT de novo HCC as either donor or recipient by using molecular analysis.

Methods: Using the LT database (2000-2019), a search was performed for patients who developed de novo HCC and underwent a second LT. Archival formalin-fixed, paraffin-embedded blocks were retrieved. Fragment analysis of 16 polymorphic short tandem repeat (STR) loci was performed on the de novo tumor, background allograft liver, and a recipient control tissue. The origin of the de novo HCC was determined by comparing the informative STR-polymerase chain reaction products from the 3 different specimen sources.

Results: Histologically, the HCC showed well to moderately differentiated morphology. Obliterative portal venopathy (OPV) was seen in all 4 cases, and 2 cases showed nodular regenerative hyperplasia (NRH); cirrhosis was absent in all cases. All HCCs were of donor origin.

Conclusions: Our study shows that in this cohort, all de novo HCCs were of donor origin, and OPV/NRH was a common concurrent finding. Short tandem repeat analysis is helpful in differentiating whether HCC in the appropriate post-LT clinical setting is of donor origin.