Primary lymphoepithelioma-like carcinoma of the lung. A clinicopathologic study of 11 cases.

Abstract

Lymphoepithelioma-like carcinoma (LELC), best known to occur in the nasopharynx, can arise in a variety of sites, such as the salivary gland, thymus, lung, stomach, and skin. Primary LELC of the lung is very rare, with only limited information in the literature. The clinicopathologic features of 11 patients with pulmonary LELC collected from two regional hospitals in Hong Kong are described. The patients, all Chinese, were aged 38 to 73 years (median, 54 years), with equal sex incidence. Two of the 8 patients were smokers. Four presented with coin lesions incidentally discovered on chest X-ray, five with cough and blood-stained sputum, and two with pleural effusion. The tumor formed a discrete (9 patients) or an ill-defined (1 patient) nodule in the lung, or, rarely, showed extensive bilateral pulmonary involvement (1 patient). The major bronchi were not involved except in 1 patient. Three patients had lymph node metastasis at presentation; two of them had bone metastasis, one at presentation and one after 9 months. The tumors had pushing margins, and grew in the form of anastomosing islands and sheets, comprising syncytial-appearing large cells with vesicular nuclei and prominent nucleoli. They were infiltrated by an appreciable number of small lymphocytes and plasma cells. Intratumoral amyloid globules were found in one tumor. In five patients, the tumor showed intraepithelial growth within the small bronchi; this could represent either the in-situ phase of the tumor or pagetoid spread into the bronchial epithelium. The neoplastic cells of all patients harbored Epstein-Barr virus (EBV) as demonstrated by in situ hybridization for EBV-encoded small nuclear RNAs. All eight Asian patients with pulmonary LELC previously reported in the literature similarly have been EBV-positive, whereas the four reported Caucasian patients all have been EBV-negative. Lymphoepithelioma-like carcinoma of lung occurring in Asians is an EBV-associated neoplasm; it also appears to occur at a higher frequency in Asians than Caucasians. It usually presents as a solitary subpleural nodule, and there is no strong association with cigarette smoking. Most patients have early stage disease at presentation. From the limited available data, the behavior of LELC of lung is highly variable, ranging from apparent curability by excision (particularly for localized disease) to highly aggressive, extensive disease at presentation.