Primary extranodal natural killer/T-cell lymphoma of bronchus and lung: A case report and review of literature.

Primary pulmonary non-Hodgkin's lymphoma (NHL) is very rare. It represents less than 1% of all NHL, and 0.5-1% of all primary pulmonary malignancies. Almost all cases of primary pulmonary NHL originate from B-cell lineage. We present a case of a 53-year-old man with primary extranodal NK/T-cell lymphoma of the bronchus and lung, presented progressive dyspnea caused by right lower lung consolidation, and pleural effusion. Initial chest computed tomography suggested advanced lung cancer. Bronchofiberscopy showed a polypoid tumor on which a biopsy was performed. Histologically, the diffusely infiltrative atypical cells were positive for cytoplasmic CD3, CD56, granzyme B, and negative for cytokeratin, CD20 immunostains, suggesting NK/T cell lineages. In situ hybridization for Epstein-Barr virus encoded ribonucleic acid (EBER) was positive. Herein, we discuss the clinicopathological features of this case and review the literature on primary extranodal NK/T-cell lymphoma of the lung. Compared with other patients, who died after the first cycle of chemotherapy and/or within three months, our patient had longer survival under aggressive chemotherapy and auto-peripheral blood stem cell transplantation.