Posttransplant lymphoproliferative disorder (PTLD) after allogeneic hematopoietic cell transplantation (HCT) is usually donor derived, associated with Epstein–Barr virus (EBV), and of B-cell origin. T-cell PTLD (T-PTLD) after allogeneic HCT is extremely rare. Four of 1015 (0.39%) allogeneic HCT patients were diagnosed with T-PTLD; peripheral T-cell lymphoma-not otherwise specified, anaplastic large cell lymphoma, monomorphic T-cell PTLD and polymorphic PTLD with chronic active EBV infection-like symptoms. Three of the four patients developed T-PTLD within 6 months after HCT from HLA-mismatched unrelated donor. Three (75%) and 4 (100%) cases were positive for EBV-encoded small RNA in situ hybridization and EBV-DNA load in peripheral blood, respectively. Chimerism analysis showed that 75% of T-PTLD tissues (3/4) were recipient derived. T-PTLD was refractory to salvage chemotherapy and fatal in all four patients. Including the 10 patients in the literature, the median interval from HCT to diagnosis of T-PTLD was 5 months (range 1–72 months), 55% were negative for EBV, and 56% were recipient-derived. T-PTLD, which often occurred early after allogeneic HCT, was more likely to be EBV negative and recipient derived than B-cell PTLD after allogeneic HCT. Like T-PTLD after solid organ transplant, T-PTLD after allogeneic HCT demonstrated morphological heterogeneity and poor prognosis.
