Treatment of recurrent posttransplant lymphoproliferative disorder of the central nervous system with high-dose methotrexate.

Posttransplant lymphoproliferative disorder (PTLD) is a frequent complication of intestinal transplantation and is associated with a poor prognosis. There is currently no consensus on optimal therapy. Recurrent PTLD involving the central nervous system (CNS) represents a particularly difficult therapeutic challenge. We report the successful treatment of CNS PTLD in a pediatric patient after liver/small bowel transplantation. Initial immunosuppression (IS) was with thymoglobulin, solucortef, tacrolimus, and mycophenolate mofetil. EBV viremia developed 8 weeks posttransplantation, and despite treatment with cytogam and valganciclovir the patient developed a polymorphic, CD20+, EBV+ PTLD with peripheral lymphadenopathy. Following treatment with rituximab, the lymphadenopathy resolved, but a new monomorphic CD20-, EBV+, lambda-restricted, plasmacytoid PTLD mesenteric mass emerged. Complete response of this PTLD was achieved with 6 cycles of cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) chemotherapy; however, 4 months off therapy he developed CNS PTLD (monomorphic CD20-, EBV+, lambda-restricted, plasmacytoid PTLD) of the brain and spine. IS was discontinued and HD-MTX (2.5-5 gm/m(2)/dose) followed by intrathecal HD-MTX (2 mg/dose ×2-3 days Q 7-10 days per cycle) was administered Q 4-7 weeks. After 3 cycles of HD-MTX, the CSF was negative for malignant cells, MRI of head/spine showed near-complete response, and PET/CT was negative. The patient remains in complete remission now for 3.5 years after completion of systemic and intrathecal chemotherapy. Conclusion. HD-MTX is an effective therapy for CNS PTLD and recurrent PTLD that have failed rituximab and CHOP chemotherapy.