DIAGNOSTIC CAPABILITIES OF FINE NEEDLE ASPIRATION OF LYMPH NODES METASTASES OF PRIMARY PULMONARY LYMPHOEPITHELIAL CARCINOMAS

Abstract

Introduction. Primary pulmonary lymphoepithelial carcinoma is a poorly differentiated squamous cell carcinoma admixed with variable amounts of lymphoplasmacytic infiltrate, frequently associated with EBV. It is a rare cancer and have a better prognosis than other non-small cell lung cancer. The tumor can mimic metastatic non-keratinizing SCC of the naso-pharynx, poorly differentiated non-small cell carcinoma and NUT carcinoma arising in the lung, and non-Hodgkin lymphomas. Materials and methods. A 75-year-old man presented with peripheral mass of left lower lobe, maximal diameter was 5.1 cm, involving lingula and medial pleura, with mediastinal, and retroperitoneal lymphadenopathy revealed by computer tomography. Fine needle aspiration-EBUS was performed from hilar and interlobar lymph nodes. Papanicolaou smears and cell blocks were prepared. Additional CT-guided cor-needle biopsy and FNA were performed from lung lesion later. Results. A few large malignant epithelial cells, consistent with non-small lung cancer, were found on a background of lymphocytes in fine-needle aspiration from lymph nodes. Immunostain results: Pan-CK (AE1/AE3), p63 and Ki67 were positive in malignant cells, leukocyte common antigen (CD45) was positive in lymphocytes (negative in tumor cells), and negative markers were TTF1, chromogranin and synaptophysin. Cytological diagnosis was metastatic non-small lung cancer, favor squamous cell carcinoma. Biopsy and aspiration from left lung showed syncytial groups of large malignant epithelial cells with scant cytoplasm and prominent nucleoli on a background of prominent inflammatory infiltrate,consistent with lymphoepithelial carcinoma. Conclusion. It is impossible to correctly diagnose metastasis of lymphoepithelial carcinoma in lymph node by FNA only without FNA or biopsy of primary lesion, because cytological features and immunostains are identical to non-keratinizing squamous cell carcinoma.