T-cell acute lymphoblastic leukaemia after liver transplantation: post-transplant lymphoproliferative disorder or coincidental de novo leukaemia?

Post-transplant lymphoproliferative disorders 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 18-year-old man who had undergone three liver transplants, initially for biliary atresia and subsequently for graft failure due to chronic rejection. He had received immunosuppression with cyclosporine and tacrolimus, as well as short-term treatment with OKT3. The T-ALL occurred 16 years after the first liver transplant. 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 post-transplant lymphoproliferative disorders. Given the long interval between the liver transplants 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 are discussed.