[Pyothorax-associated lymphoma with the expression of Epstein-Barr virus latent genes].

An 84-year-old man, who had received artificial pneumothorax for pulmonary tuberculosis 67 years previously, complained of severe chest pain. Chest CT revealed chronic pyothorax with multiple heterogeneously enhanced cavity lesions in the wall of the right intrathoracic space. ¹⁸ FDG-PET revealed that the lesions showed an abnormal uptake. CT-guided biopsy was performed and he was diagnosed with pyothorax-associated lymphoma (PAL); the histological diagnosis was diffuse large B cell lymphoma (DLBCL). Furthermore, immunohistochemical staining revealed that the tumor cells were positive for EBNA-2 and LMP-1, suggesting that the latent gene products of Epstein-Barr virus were associated with the development of PAL. The patient was treated with chemotherapy, including rituximab; however, the treatment was discontinued due to the development of severe delirium after chemotherapy. We should keep in mind that elderly patients with a long history of chronic pyothorax are at risk of developing malignant lymphoma. We report the present case with a brief review of the literature.