[Lymphoma in patients who have undergone organ transplantation: severe and variable clinical presentation]

Two patients presented with post-transplant lymphoproliferative disorder (PTLD). PTLD encompasses a broad range ofoften malignant proliferations of lymphoid tissue arising in the immunocompromised host after transplantation. The first patient, a 62-year-old woman, received a bilateral lung transplant due to end-stage emphysema and was diagnosed with PTLD 27 days after transplantation. Treatment consisted of reduction in immunosuppression and administration of rituximab. The PTLD regressed. The second patient, a 57-year-old woman, presented with a massively disseminated PTLD 12 years after kidney transplantation. Immunosuppression was reduced and rituximab was administered, but no response was observed. Despite salvage chemotherapy, the patient died due to progressive disease. These two cases illustrate the heterogeneous presentation of PTLD. The condition is caused by the proliferation of B lymphocytes infected with Epstein-Barr virus (EBV) that are no longer controlled by EBV-specific cytotoxic T lymphocytes, due to the immunosuppressive medication given to prevent transplant rejection. Regression of the lymphoma may be achieved by reducing the immunosuppression or treating with rituximab, which attacks B lymphocytes.