PRIMARY LYMPHOEPITHELIOMA-LIKE CARCINOMA OF THE LUNG - A CLINICOPATHOLOGICAL STUDY OF 11 CASES

Background. Lymphoepithelioma-like carcinoma (LELC), best known to occ ur in the nasopharynx, can arise in a variety of sites, such as the sa livary gland, thymus, lung, stomach, and skin. Primary LELC of the lun g is very rare, with only limited information in the literature. Metho ds. The clinicopathologic features of 11 patients with pulmonary LELC collected from two regional hospitals in Hong Kong are described. Resu lts. The patients, all Chinese, were aged 38 to 73 years (median, 54 y ears), with equal sex incidence. Two of the 8 patients were smokers. F our presented with coin lesions incidentally discovered on chest X-ray , five with cough and blood-stained sputum, and two with pleural effus ion. The tumor formed a discrete (9 patients) or an ill-defined (1 pat ient) nodule in the lung, or, rarely, showed extensive bilateral pulmo nary involvement (1 patient). The major bronchi were not involved exce pt in 1 patient. Three patients had lymph node metastasis at presentat ion; two of them had bone metastasis, one at presentation and one afte r 9 months. The tumors had pushing margins, and grew in the form of an astomosing islands and sheets, comprising syncytial-appearing large ce lls with vesicular nuclei and prominent nucleoli. They were infiltrate d by an appreciable number of small lymphocytes and plasma cells. Intr atumoral amyloid globules were found in one tumor. In five patients, t he tumor showed intraepithelial growth within the small bronchi; this could represent either the in-situ phase of the tumor or pagetoid spre ad into the bronchial epithelium. The neoplastic cells of all patients harbored Epstein-Barr virus (EBV) as demonstrated by in situ hybridiz ation for EBV-encoded small nuclear RNAs. All eight Asian patients wit h pulmonary LELC previously reported in the literature similarly have been EBV-positive, whereas the four reported Caucasian patients all ha ve been EBV-negative. Conclusion. Lymphoepithelioma-like carcinoma of lung occurring in Asians is an EBV-associated neoplasm; it also appear s to occur at a higher frequency in Asians than Caucasians. It usually presents as a solitary subpleural nodule, and there is no strong asso ciation with cigarette smoking. Most patients have early stage disease at presentation. From the limited available data, the behavior of LEL C of lung is highly variable, ranging from apparent curability by exci sion (particularly for localized disease) to highly aggressive, extens ive disease at presentation.