[Clinical characteristics of lung NK/T cell lymphoma misdiagnosed as pneumonia]

Objective: To investigate the clinical features of lung natural killer (NK)/T cell lymphoma. Methods: The clinical data of patients with lung NK/T-cell lymphoma confirmed by pathology who were hospitalized due to lung shadow and initially treated as pneumonia from the First Affiliated Hospital of Zhengzhou University was collected from June 2013 to January 2019. The clinical manifestations, laboratory tests, chest CT findings, treatment procedures, outcomes, and misdiagnosis were retrospectively analyzed. Results: Among the 15 enrolled patients with lung NK/T-cell lymphoma, 5 were primary and the other 10 were secondary. There were 8 males and 7 females, aged 20-76 years. Fever presented in 14 cases, dyspnea was observed in 4 cases and 2 cases had cough. A total of 12 cases had leukopenia, 10 cases had mononuclear cell increase, 10 cases had liver dysfunction, 13 cases had elevated serum lactate dehydrogenase (LDH), and 2 cases of primary lung NK/T-cell lymphoma had increased pleural LDH and adenosine deaminase. Five cases of primary lung NK/T-cell lymphoma had multiple lung lesions, with diffuse multiple solid shadows, ground glass and patchy shadows, some with nodules; 10 cases of secondary lung NK/T-cell lymphoma showed nodular masses, some were accompanied by patchy shadows, and most patients had multiple lesions scattering in the lung. All the fifteen patients were misdiagnosed as pneumonia in the early stage, and then were diagnosed by percutaneous lung biopsy or transbronchial biopsy. Six patients underwent chemotherapy, of which 1 achieved complete response, 4 were in follow-up and 1 died of respiratory failure; 5 patients died of respiratory failure after diagnosis and 4 patients discharged and died within half a year. Conclusions: The lung NK/T-cell lymphoma are rare. The clinical manifestations and pulmonary imaging findings are indistinguishable from pulmonary inflammatory lesions. They are easily misdiagnosed as pneumonia. Early CT-guided percutaneous lung biopsy or transbronchial biopsy can improve the diagnostic accuracy.