Purpose or Case Report: Post-Transplant Lymphoproliferative Disease (PTLD) is a polyclonal and monoclonal lymphoid proliferation which occurs in 1-20% of solid organ transplant recipients. It is most common in multivisceral organ transplants followed by small bowel transplants, heart and lung transplants and less commonly in liver and kidney transplants. PTLD has a bimodal distribution of occurrence with the largest peak occurring within 1 year after transplantation and a second peak at approximately 4-5 years after transplantation. The Epstein Barr virus (EBV) is associated in 50-70% of cases. EBV seronegativity in the recipient at the time of transplant predicts a 2-4 times increased risk of PTLD especially if they receive a donor organ which is positive for EBV. This may explain the higher incidence in the pediatric population who tend to be seronegative for EBV. The World Health Organization (WHO) identifies four pathologic categories of PTLD: early lesions, polymorphic type, monomorphic type and classic Hodgkins lymphoma. The majority of PTLD cases are caused by B-lymphocyte proliferation in a T-cell depleted environment in the setting of immunosuppression. However, there is a subset of cases that are caused by T-cell or natural killer cells as well as cases that occur in the setting of negative EBV. Multiple clones of proliferating B-cells can be seen in a single patient. 2/3 of cases have diffuse expression of CD20 which is an important target for therapy.

PTLD may be focal or diffuse and can manifest in a variety of different organ systems or even in the allograft itself. There is a higher percentage of extranodal disease in PTLD as compared to immunocompetent patients with lymphoma. The GI tract and liver are most commonly involved. Isolated lymph node involvement in comparison is less common in patients with PTLD. Central nervous system (CNS) involvement is relatively rare in PTLD.

This educational exhibit will provide a pictorial review of PTLD and illustrates cases from one of the busiest transplant centers in North America to highlight the major imaging findings as well as complications seen on imaging of this disease. Extranodal and nodal disease will be demonstrated on multiple modalities as well as complications of this disease including intussusception and biliary obstruction. CNS disease will also be shown. The clinical manifestations, imaging characteristics, prognosis and treatment will be discussed and depicted.
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