Background: Pyothorax-associated pleural lymphomas (PAPL) occur in patients with long-standing pyothorax. Epstein-Barr virus (EBV) plays an important role in its development.
Methods: An atypical case of PAPL is reported and its clinical features are compared with those of five cases of ordinary PAPL.
Results: The histology of the lymphoma changed from prominent T-cell infiltration to an overt B-cell lymphoma of diffuse, large cell-type. DNA studies of the lymphoma at the first presentation demonstrated dual rearrangement in the T-cell receptor beta (TCR beta) and immunoglobulin heavy chain J region (IgJH) genes. EBV genome analysis demonstrated monoclonal expansion of EBV-infected cells. EBV gene products were present only in large lymphocytes with B-cell phenotype. The same rearranged band of the IgJH gene, but not clonal rearrangement of the TCR beta gene, was observed in the overt B-cell lymphoma at the relapse. The same EBV-infected clone was observed throughout the course of the disease. The tumor was localized at the pyothorax wall, and cell-mediated immunity, reflected by a positive tuberculin reaction, was preserved only in the current case.
Conclusions: T-cell-rich lymphoid infiltration in the current case is a variant of EBV-associated PAPL, which is infiltrated by reactive T-cells with clonal accentuation. This is the first documented case of EBV-associated PAPL evolving from T-cell-rich lymphoid infiltration.