[An autopsy case of B lymphoblastic leukemia/lymphoma with hemophagocytic syndrome infiltrating in the central nervous systems].

The hemophagocytic syndrome(HPS) after the hematopoietic stem cell transplantation(SHCT) may be triggered by the reactivation of virus such as Epstein-Barr virus (EBV) or cytomegalovirus (CMV) under immunosuppressive state. The present case was a 17-year old man who was diagnosed as B lymphoblastic leukemia. Bone marrow aspiration showed 96.4% of lymphoblasts with positive for CD19 and CD20, negative for CD66 and POX, and dot staining for PAS. E2A/PBX1 chimeric mRNA was positive as assessed by RT-PCR method. He received three courses of induction chemotherapy followed by allo-bone marrow transplantation (BMT) from his sister, but had a relapse three months after allo-BMT. He received allo peripheral blood-SCT (PBSCT) from his mother. The hematopoietic cells successfully engrafted, but the mixed chimerism of 2 donors persisted. On day 149, he had a fever, and hemophagocytosis was found by bone marrow aspiration. EBV genomic DNA was detected for 1.62 x 10(3) copies. CMV and fungus were negative in blood. On day 165, the patient had been observed disturbance of consciousness, neck stiffness, and died on day 170 due to multiple organ failure. Autopsy examination showed infiltration of CD20+ leukemic cells into the perivascular space of cerebrum, brainstem and spinal cord, with hemophagocytosis by CD6+ macrophages. In situ hybridization of EB-virus encoded small RNA (EBER) confirmed EBV infection of B-lymphoblastic cells infiltrated in the cerebrum. HPS was considered to be triggered by the reactivation of EBV, due to hematopoietic dysfunction based on long-term immunosuppressive treatment and mixed chimerism derived from a HSCT from 2 donors.