Checkpoint Inhibition in the Treatment of Unresectable, Advanced Lymphoepithelioma-like Hepatocellular Carcinoma.

Lymphoepithelioma-like hepatocellular carcinoma (LEL-HCC) is a very rare neoplasm, with distinct epidemiologic, morphologic and clinical characteristics. Molecular mechanistic insight into the pathogenesis of this carcinoma suggests a pivotal role for the host immune system in the proliferation and progression of this tumor. However, while detailed genomic profiling of these hepatic tumors have revealed an intra-tumoral inflammatory mutational signature that may predispose to immune checkpoint inhibitor efficacy, no published report has described their use in this tumor type. Unfortunately, with near 100 cases of LEL-HCC reported in the literature to date and the majority of cases confined to localized and resectable disease, current evidence-based practices in the unresectable setting are lacking, with unknown benefit of chemotherapy or immunotherapy. We report on the case of a 68 year-old man with unresectable, advanced LEL-HCC who had evidence of disease stability after starting on the immune checkpoint inhibitor nivolumab. His disease response persisted off therapy for over a year and was potentially augmented by radiotherapy at the site of local progression. For this extremely rare tumor subtype, this case highlights the potential efficacy and safety of immune checkpoint blockade in LEL-HCC and reinforces the need for more robust, large-scale analysis of patients with these rare tumors to better evaluate treatment strategies and outcomes.