Posttransplant lymphoproliferative disorder complicating hematopoietic stem cell transplantation in a patient with dyskeratosis congenita.

Dyskeratosis congenita (DC) is a rare inherited disorder characterized by bone marrow failure and cancer predisposition. We present a case of a 28-year-old woman with DC who was admitted for hematopoietic stem cell transplantation (HSCT) for aplastic anemia and who developed acute myeloid leukemia with complex genetic karyotype abnormalities including the MLL (11q23) gene, 1q25, and chromosome 8. After transplantation, a monomorphic Epstein-Barr virus (EBV) negative posttransplant-associated lymphoproliferative disorder (PTLD) diffuse large B-cell lymphoma was discovered involving the liver, omental tissue, and peritoneal fluid samples showing additional MLL (11q23) gene abnormalities by fluorescence in situ hybridization. Despite treatment, the patient died of complications associated with transplantation and invasive fungal infection. This case represents the first bona fide documented case of EBV-negative monomorphic PTLD host derived, with MLL gene abnormalities in a patient with DC, and shows another possible mechanism for the development of a therapy-related lymphoid neoplasm after transplantation.