To investigate the clinicopathological features, diagnosis and differential diagnosis of pulmonary extranodal NK/T-cell lymphoma, nasal type (ENKTL-NT).

Eleven cases of newly diagnosed (10 puncture biopsies and 1 transbronchial biopsy), previously untreated pulmonary ENKTL-NT were collected at the First Affiliated Hospital of Zhengzhou University, from August 2013 to November 2018. The clinicopathological features including histomorphology, immunohistochemistry and in situ hybridization were collected and analyzed.

Among the 11 cases, 8 were males and 3 were females, with a male to female ratio of 8∶3.The age range was from 30 to 74 years, with an average of 48 years and a median of 43 years. Tumors involved bilateral lung lobes in 8 cases, the upper left lobe in 1 case, lower left lobe in 1 case, and upper right lobe in 1 case. Main clinical symptoms included fever, often accompanied by cough, and bloody sputum in most cases. All cases were stage Ⅳ E. Histological features included scattered or focal aggregates of marked pleomorphic tumor lymphocytes, accompanied by necrosis and heavy admixture of inflammatory cells. In a few cases, diffuse neoplastic lymphocytes or vascular central and destructive infiltrations were seen. Tumor cells in most cases expressed CD3ε, CD3, CD43, CD56, TIA-1, granzyme B, but did not express CD20, CD79a, and CD5. Ki-67 index ranged from 40%to 90%.All cases were positive for EBER by in situ hybridization. Four of five patients died during follow-up with a survival period of only 1 week to 13 months.

Pulmonary ENKTL-NT is rare, high grade malignancy with a poor prognosis. Misdiagnosis is common due to lesional necrosis and heterogeneous cell components. Immunohistochemistry and EBER in situ hybridization are essential for accurate diagnosis.

Lung neoplasms; Lymphoma, extranodal NK-T-cell; Immunohistochemistry