An adult case of systemic Epstein-Barr virus-positive T/natural killer-cell lymphoproliferative disorder with good outcome.

Epstein-Barr virus-positive T/natural killer (NK)-cell lymphoproliferative disorder (EBV+T/NK LPD) encompasses a heterogeneous group of disorders that have a common feature with excessive lymphoid proliferation of mainly T cells and/or NK cells. This disease is rare, predominantly affects children and young adults, and associated with high mortality. Herein, we report a case of EBV+T/NK LPD that occurred in an old woman with good outcome. The patient presented with fever, splenomegaly, and pancytopenia. Computed tomography (CT) scan of the abdomen showed splenomegaly. The clinical impression was a malignant tumor of spleen, so splenectomy was performed. Microscopically, the architecture of the spleen was preserved. The white pulp Malpighian corpuscles were atrophied. The red pulp showed intact sinusoids and pulp cords with increased cellular infiltrate. The proliferating lymphoid cells were mostly small lymphoid cells with minimal or no nuclear atypia, mixed with rare medium-sized or large cells. Immunohistochemical study and in-situ hybridization showed that the EBER-positive lymphoid cells were positive for CD3 and CD56. They were also positive for cytotoxic molecules, such as T-cell restricted intracellular antigen (TIA1), granzyme B. The case exhibited polyclonal rearrangement of T-cell receptor gene (TCR) by polymerase chain reaction (PCR) studies. Without radiotherapy and chemotherapy, the patient is alive and well with no evidence of disease 25 months after surgery.