Introduction: Post-transplant lymphoproliferative disorders (PTLD) are a heterogeneous set of complications of organ transplantation associated with poor patient prognosis. Here we present the clinicopathological features of a single center series of 26 cases.

Materials and Methods: All of the 2224 solid organ transplant recipients who underwent transplantation between 1985 and 2013 in Baskent University were included in this study. Demographic and clinical findings of these patients baseline immunosupressive therapy, and the time between transplantation and the development of PTLD were examined in all cases. Among cases whom have been diagnosed as having PTLD were (re)-classified according to the WHO 2008 classifications of lymphomas. Three main pathologic subsets / stages of evolution are recognised: early, polymorphic, and monomorphic lesions. The grading of PTLD and the association of PTLD with EBV were compared. The causes of death were also evaluated.

Results: Of 2224 solid organ transplant recipients, 26 cases(1.16%), developed heterogeneous types of PTLDs. The cumulative incidences of PTLDs during this period were 0.86% (15 / 1740) for kidney transplant recipients and 2.69% (11 / 408) for liver transplant recipients. PTLDs had not developed in 76 heart transplant recipients. Mean interval between the first transplantation and the diagnosis of PTLD was 64,6 ±70 months (range, 4-248 months). Among 26 cases only 7 patients developed PTLD with in the 1st year of transplantation. The mean age at the time of PTLD diagnosis was 27.3 ± 18 years (range, 1-52 years) and eight patients (30.8%) were younger than 19 years at the time of PTLD diagnosis. There was a male predominance (16 cases 61.5%) among patients with PTLD. The gastrointestinal tract was the organ system most commonly involved (9/26, 34.6%) in our cases. The second highest PTLD involvement was found in lymph nodes in 5 cases. Only 3 cases showed PTLD involvement in the allograft. Of 26 cases 23 of them showed monomorphic PTLD, while only 1 case showed polymorphic PTLD and remaining 2 cases showed early lesion. Total of 26 cases 8 of them died 37.9±49.9 months (range 0.3-131 months) after the PTLD diagnosis because of the complication of transplantation and/or the PTLD.

Conclusions: Immunophenotyping PTLD’s is essential because of the significant differences in prognosis and therapy between B-cell and NK / T cell lymphomas. Sampling of several lesions in cases with multiple site involvement is also essential because early, monomorphic and polimorphic lesions can be synchronously present in different sites. In conclusion, even with treatment the mortality rate is high in patients with PTLD. Thus in order to decrease the incidence of PTLD and related mortality, the risk factors should be evaluated and the new approaches must be derive for prophylaxis, diagnosis and treatment.