Epstein-Barr virus-related post-transplant lymphoproliferative disorder occurring after bone marrow transplantation for aplastic anemia in Down's syndrome.

It is well established that Down's syndrome exhibits a predisposition to development of leukemia, however, association between aplastic anemia and Down's syndrome is exceptional. Herein, we describe a case of aplastic anemia occurring in Down's syndrome following post-transplant lymphoproliferative disorder (PTLD) after bone marrow transplantation (BMT). A 27-year-old Japanese male with Down's syndrome presented with a headache. Laboratory tests revealed severe pancytopenia, and bone marrow biopsy demonstrated hypocellular bone marrow with decrease of trilineage cells, which led to a diagnosis of aplastic anemia. One year after diagnosis, he was incidentally found to have an anterior mediastinal tumor, which was histopathologically diagnosed as seminoma. Subsequently, he received BMT from a female donor, and engraftment was observed. Three months after transplantation, he experienced cough and high fever. Biopsy specimen from the lung revealed diffuse proliferation of large-sized lymphoid cells expressing CD20 and EBER. These lymphoid cells had XY chromosomes. Thus, a diagnosis of EBV-associated PTLD was made. This is the seventh documented case of aplastic anemia occurring in Down's syndrome. Association between aplastic anemia and Down's syndrome has not been established, therefore, additional clinicopathological studies are needed. Moreover, this is the first case to undergo BMT for aplastic anemia in Down's syndrome. Although engraftment was observed, he developed EBV-positive PTLD. The neoplastic cells of the present case were considered to be of recipient origin, although the majority of PTLD cases with BMT are of donor origin.