Appearance of a different clone of Epstein–Barr virus genome in recurrent tumor of pyothorax-associated lymphoma (PAL) and a mini-review of PAL

Abstract

A case of pyothorax-associated lymphoma (PAL) is reported. A 76-year-old Japanese man developed a lymphoma in the pleural cavity after 46 years duration of pyothorax due to pulmonary tuberculosis. The histologic diagnosis of biopsy specimen was diffuse large cell lymphoma of B cell type. The lymphoma cells contained the monoclonal Epstein–Barr virus (EBV) determined by the analysis of terminal repeat of EBV genome and expressed EBV nuclear antigen 2 and latent membrane protein 1 (LMP1). He received antineoplastic chemotherapy and was induced to complete remission (CR). After 19 months of CR, the lymphoma developed again in the thoracic wall. Histopathology and immunohistochemical phenotypes of recurrent tumor were almost the same as those of the primary tumor with the exception of a little more frequent expression of LMP1. The EBV genome in lymphoma cells was monoclonal, however, the clone was different from that of the primary tumor. After antineoplastic chemotherapy, minor EBV-positive clones in primary lymphoma might survive and develop into recurrent tumor. These results suggest that the PAL starts as poly- or oligoclonal proliferation of B lineage cells. This poly- or oligoclonality of PAL at the initial stage may suggest underlying immunosuppressive conditions in the development of PAL.