Lymphoepithelioma-Like Carcinoma of the Lung. Two Cases Diagnosed in Caucasian Patients

Lymphoepithelioma-like carcinoma is a non-nasopharyngeal undifferentiated carcinoma with prominent lymphoid infiltration. Ten cases arising in the lung have been reported so far; seven cases were diagnosed in Orientals, with the Epstein-Barr virus (EBV) genome demonstrated in neoplastic cells by in situ hybridization; the remaining three cases affected Caucasian patients and showed no evidence of hybridized viral genome. The present study describes two additional cases of lymphoepithelioma-like carcinoma of the lung in Caucasians, with reference to the differential diagnosis versus other thoracomediastinal malignancies. The neoplastic nuclei, blastlike in appearance, together with the immunohistochemical profile of the neoplastic cells (positivity for cytokeratins, and negativity for CD antigens, S100 protein, placental alkaline phosphatase, and neuroendocrine markers) represent the basic pathologic features of a lymphoepithelioma-like carcinoma and allow its recognition even on small bioptic fragments, in which the typical biphasic, Regaud-like morphology might be inapparent. In accordance with the previously reported cases of pulmunary lymphoepithelioma-like carcinoma in Caucasian patients, the present study found no evidence of the Epstein-Barr virus genome in neoplastic cells with in situ hybridization.