T cell lymphoproliferative disorder following bone marrow transplantation for severe aplastic anemia

Post-transplant lymphoproliferative disorder (PTLD) is uncommonly of T cell. origin, especially following BMT, We describe a 13-year-old boy with severe aplastic anemia (SAA) and no evidence of Fanconi's anemia who underwent BMT at 11 years of age using CY 10 mg/kg once daily i.v. on days -5, -4, antilymphocyte globulin (ALG) 30 mg/kg once daily i.v. on days -5 similar to -3 and CsA from day -1 as conditioning. The BMT failed and he received a further peripheral blood stem cell transplant (PBSCT) 240 days after BMT, Conditioning was with CY 50 mg/kg once daily i.v. on days -5 similar to -2, and ALG 15 mg/kg once daily i.v. on days -4 similar to -2. GVHD prophylaxis included CsA and MTX, Engraftment was later confirmed by cytogenetic studies. Desquamation and ulcers of the oral mucosa and mouth angle developed in the 13th month post PBSCT, A buccal mucosa biopsy on day +524 revealed only plasmacytosis, Immunosuppressants were discontinued at that point. Generalized lymphadenopathy, prolonged fever (waxing and waning) and facial swelling developed in the 18th month post PBSCT, A neck lymph node biopsy on day +601 showed T cell lymphoma of diffuse large cell type with monoclonal TCR gamma -chain gene rearrangement. A FISH study showed that the malignant T cells were of recipient origin. EBV in situ hybridization was negative. He did not receive further treatment apart from discontinuation of immunosuppressants, He was followed up in our out-patient clinic and showed good performance 1170 days post PBSCT, We speculate that a different mechanism was operating in the pathogenesis of T cell lymphoma in this case. Risk factors include SAA and two transplants, conditioned with CY and ALG, long term use of CsA and treatment with azathioprine.