Occurrence of Epstein-Barr virus-associated plasmacytic lymphoproliferative disorder after antithymocyte globulin therapy for aplastic anemia: a case report with review of the literature.

It is well established that patients with immunosuppression have a higher risk of development of lymphoproliferative disorders (LPDs), and Epstein-Barr virus (EBV) is associated with development of LPDs. Aplastic anemia (AA) is an immune-mediated hematological disorder, and immunosuppression therapy (IST), such as antithymocyte globulin (ATG), is widely used for treatment of AA. However, occurrence of LPD without bone marrow transplantation has been extremely rarely documented in patients with IST for AA. Herein, we report the 6th documented case of EBV-associated LPD after IST for AA and review the clinicopathological features of this extremely rare complication. A 46-year-old Japanese female was admitted for evaluation of progressive pancytopenia. Bone marrow biopsy revealed fatty marrow with marked decrease of trilineage cells, and bone marrow aspiration demonstrated no dysplastic changes. IST with rabbit ATG was administered, after which, she developed high fever. Bone marrow aspiration showed increase of atypical plasma cells with mildly enlarged nuclei and irregular nuclear contour. These atypical plasma cells were EBER-positive. Accordingly, a diagnosis of EBV-positive plasmacytic LPD was made. Most cases of LPDs are B-cell origin, and plasmacytic LPD is a rare subtype. The current report is the second case of plasmacytic LPD in patients with IST for AA. Therefore, detailed histopathological and immunohistochemical analyses are needed for correct diagnosis and treatment, and additional studies are needed to clarify the clinicopathological features of EBV-LPD after IST for AA.