Introduction: Post-transplant lymphoproliferative disorders (PTLD) of T-cell origin are quite uncommon, and the vast majority represent neoplasms of mature, post-thymic T- or natural killer cells. Here, we report a rare case of T-cell acute lymphoblastic leukaemia (T-ALL), which occurred in an 3-year-old child who had undergone liver transplantation for the reason of hepatoblastoma.

Case Report: Three-years old male patient whom had liver transplantation because of hepatoblastoma had neither liver allograft failure nor rejection episode during fallow-up of twenty-two months. Twenty-two months after liver transplantation patient came to the hospital with the complaint of severe cough. Thoracal CT scan which was taken for this reason showed a large mediastinal mass measuring 9x7.2x7cm. The needle-guided biopsy of the mass noted a diffuse infiltration of blastic cells which was accepted as T-ALL infiltration. The patient recieved methotrexate and, prednisolone for the T-ALL treatment, and he was died two months after the diagnosis due to chemotherapy-related sepsis.

Conclusions: This case highlights the challenge for classifying rare neoplasms occurring in recipients of solid organ transplants that are currently not recognized to lie within the spectrum of PTLD. Given the long interval between the liver transplantation and the development of T-ALL, a coincidental occurrence of the leukaemia cannot be ruled out. However, the potential roles of immunosuppressive therapy and other co-morbid conditions of the individual as possible risk factors for the pathogenesis of T-ALL must be always taken in consideration.