“…Then we reviewed references of all selected articles to research additional articles. We selected 29 articles published between 1990 and December 2019, including 46 cases ( Table 1 ) ( 7 – 35 ), 22 with histological analysis (brain biopsy, spine biopsy, or autopsy) ( 7 , 8 , 10 , 13 , 17 – 19 , 22 , 25 , 27 , 29 , 30 , 32 – 34 ). Patients who had received an allogeneic HCT for hematological disease were selected if they had CNS abnormalities and other diagnosis (autoimmune disease, infectious diseases, hematologic malignancies relapse, or post transplantation lymphoproliferative disorders) were excluded.…”