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 seve re 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, an tilymphocyte 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 fu rther peripheral blood stem cell transplant (PBSCT) 240 days after BMT, Con ditioning was with CY 50 mg/kg once daily i.v. on days -5 similar to -2, an d ALG 15 mg/kg once daily i.v. on days -4 similar to -2. GVHD prophylaxis i ncluded CsA and MTX, Engraftment was later confirmed by cytogenetic studies . Desquamation and ulcers of the oral mucosa and mouth angle developed in t he 13th month post PBSCT, A buccal mucosa biopsy on day +524 revealed only plasmacytosis, Immunosuppressants were discontinued at that point. Generali zed lymphadenopathy, prolonged fever (waxing and waning) and facial swellin g 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 g amma -chain gene rearrangement. A FISH study showed that the malignant T ce lls were of recipient origin. EBV in situ hybridization was negative. He di d not receive further treatment apart from discontinuation of immunosuppres sants, He was followed up in our out-patient clinic and showed good perform ance 1170 days post PBSCT, We speculate that a different mechanism was oper ating in the pathogenesis of T cell lymphoma in this case. Risk factors inc lude SAA and two transplants, conditioned with CY and ALG, long term use of CsA and treatment with azathioprine.