P1920 - Lymphoepithelioma-Like Hepatocellular Carcinoma, a Rare Indolent Subtype of Hepatic Cancer

Rajalakshmi Govalan, MD, MS¹, Ju Dong Yang, MD, MS², Rola Saouaf, MD¹, Maha Guindi, MD¹, Nicholas Nissen, MD^1
1Cedars-Sinai Medical Center, Los Angeles, CA; ²Cedars-Sinai Medical Center, West Hollywood, CA

Introduction: Lymphoepithelioma is a tumor of undifferentiated epithelial cells with dense infiltration of lymphoid cells. Originally described in the nasopharynx, they are termed lymphoepithelial-like carcinoma (LELC) when found in other organs. Primary LELC in the liver is rare but has a favorable post-treatment prognosis compared to typical Hepatocellular carcinoma (HCC). We report an extremely indolent clinical course of pre-treatment LELC-HCC.

Case Description/Methods: A 72-year-old Hispanic female with compensated cirrhosis from treatment-naïve hepatitis C and PBC presented with liver mass. Four years prior, she had an MRI imaging for abdominal pain, which showed a nodular liver with a mass measuring 4.6 x 3.7 cm in the right hepatic lobe with heterogeneous enhancement on arterial phase with mild venous washout, concerning for HCC. She was lost to follow up until she presented with an interval increase in the mass to 6.4 x 4.8 cm (Figure 1). Pertinent labs include platelet count 149,000 /mL, albumin 3.9 g/dL, international normalized ratio 1.0, bilirubin 0.5 mg/dL, and alpha-fetoprotein 11.5 ng/mL. The staging work-up was unremarkable. She underwent segmental resection of the mass followed by microwave ablation of the resection bed for margin extension. Histopathologic examination showed poorly differentiated HCC with massive lymphocytic infiltration within the tumor, outnumbering tumor cells without lymphovascular invasion. Immunohistochemical staining showed tumor cell immunoreactivity for the hepatocellular lineage markers, Hepar-1, and Arginase 1, confirming HCC. CK-19 was negative (Figure 1). In situ hybridization for Epstein Barr virus (EBV) showed reactivity in a few of the inflammatory mononuclear cells within the tumor. The patient had an uneventful recovery with no recurrence of the tumor on surveillance.

Discussion: To date, very few cases of LELC have been reported worldwide, suggesting that this variant might have been underreported or underrecognized. Our case demonstrates, for the first time to our knowledge, the indolent pre-treatment progression of this tumor as opposed to typical HCC. This favorable prognosis might be due to the cytotoxic antitumor effect of the CD8+ T cell lymphocytes infiltrating the tumor. It remains unclear if the few EBV-positive mononuclear cells contribute to the development of LELC-HCC or if it offers a protective effect by enhancing the immune response. Understanding this unique subtype of cancer might shape the field of HCC immunotherapy in the future.



Disclosures:


Rajalakshmi Govalan, MD, MS¹, Ju Dong Yang, MD, MS², Rola Saouaf, MD¹, Maha Guindi, MD¹, Nicholas Nissen, MD¹. P1920 - Lymphoepithelioma-Like Hepatocellular Carcinoma, a Rare Indolent Subtype of Hepatic Cancer, ACG 2021 Annual Scientific Meeting Abstracts. Las Vegas, Nevada: American College of Gastroenterology.