An etiologically important role of chronic tuberculous empyema for development of pleural lymphocytic lymphoma of B-cell type has been suggested. To examine risk factors for development of pleural lymphoma in patients with chronic tuberculous empyema, a case-control study was carried out. Onset age of lung tuberculosis and empyema, presence of chemotherapy, surgical treatment, extent of empyema, presence of fistula, history of smoking, and height and weight of patients at first admission were compared in patients with empyema alone (70 controls) and empyema complicated with lymphoma (42 cases): the date of birth and sex were matched by group. The patients receiving artificial pneumothorax showed a significant increase in risk for development of pleural lymphoma (relative risk = 4.92, P < 0.05). We could not find any report describing development of pleural neoplasias in patients with chronic empyema receiving surgical resection of pleural pyogenic membrane. From these findings, it is suggested that artificial pneumothorax left chronic non-healing inflammation in the pleural cavity, which resulted in development of pleural lymphoma.