Abstract： Objective To investigate the clinical manifestations,pathological types,treatment and prognosis of primary pulmonary lymphoma (PPL) and secondary pulmonary lymphoma (SPL).Methods The clinical data of 40 cases of PPL or SPL diagnosed from 2003 to 2013 in the Chinese PLA General Hospital were retrospectively analyzed.All cases were diagnosed via lung biopsy or surgical biopsy.Results There were 24 male and 16 female patients,aging from 15 to 84 years,including 10 patients with PPL and 30 with SPL.The main clinical manifestations of PPL were cough and chest pain,but 4 patients were asymptomatic.Chest CT showed lung mass in 8 patients and patchy opacities in 3.18F-FDG PET/CT showed that the SUV of lung lesions was 3.96-6.70 with a median value of 4.50.The pathological types of all PPL cases were non-Hodgkin lymphoma (NHL),and 4 patients were treated with surgery combined with chemotherapy,and 3 patients were treated with surgery alone.The main clinical manifestations of SPL were cough,superficial lymph node enlargement and fever,but 8 patients were asymptomatic.The chest CT revealed pleural effusions in 20,mediastinal and hilar lymph node enlargement in 14,patch opacities in 13 and multiple nodules in 6 patients.In addition to pulmonary involvement,PET/CT examination confirmed that cervical lymph nodes,thyroid,stomach and pancreas were also involved.The SUVmax was from 2.40 to 19.60,with a median value of 5.70.Twenty-one cases of SPL were NHL and 9 were Hodgkin lymphomas (HL).Of these patients with SPL,14 were treated with chemotherapy alone,8 chemotherapy combined with radiotherapy,and 2 surgery combined with chemotherapy.The one-year survival rate of PPL was 100％,compared with 93.3％ of SPL.The shortest survival time of PPL was 13 months,compared with 2 months of SPL.Conclusions There were differences in the radiological features,pathological types and treatment between PPL and SPL.The chest CT manifestations of PPL were mainly lung masses,while those of SPL were mainly pleural involvement and mediastinal and hilar lymph node enlargement.The pathological type of PPL was all NHL while that of 9 cases of SPL was HL.Patients with PPL were mainly treated with surgical therapy,but SPL mainly with chemotherapy.PET/CT examination may be helpful for the diagnosis and staging of lung lymphoma.Since the misdiagnosis rate of pulmonary lymphoma was high,diagnosis must rely on lung tissue biopsy and immunohistochemistry.Compared with PPL,the prognosis of SPL is poorer.