Primary pulmonary lymphoepithelioma-like carcinoma with positive expression of Epstein-Barr virus and PD-L1: A case report.

Introduction And Importance: Pulmonary lymphoepithelioma-like carcinoma (LELC) is a rare type of non-small cell lung cancer (NSCLC) that is classified as a subtype of unclassified carcinoma by the WHO. LELC is usually associated with Epstein-Barr virus (EBV) infection. LELC has often been observed in Southeast Asia; however, it is extremely rare in Japan.

Case Presentation: A 60-year-old Japanese woman presented with an abnormal shadow in the left lung on chest radiography. Chest computed tomography showed a nodule located between the lingular and basal anteromedial segments. A blood test suggested an existing EBV infection, and LELC was suspected preoperatively in the transbronchial lung biopsy. She underwent a lingular and basal bi-segmentectomy. The EBV-encoded small ribonucleic acid in-situ hybridization (EBER-ISH) was positive, and she was diagnosed with LELC. Moreover, programmed death-ligand 1 (PD-L1) expression was moderately positive. No recurrence was observed for 30 months.

Clinical Discussion: Although LELC has been reported as a low-grade malignancy with a good prognosis, the frequency of PD-L1 expression in LELC seems to be higher than that in other NSCLCs. Moreover, it has been reported that LELC patients with high PD-L1 expression are likely to have early recurrence/metastasis and poor prognosis.

Conclusion: An investigation of PD-L1 expression for LELC would be useful considering the benefit of PD-1/PD-L1 blockade in patients with pulmonary LELC with high PD-L1 expression. The present case is the first report of LELC with positive expression of EBER-ISH and PD-L1 in Japan.