Fig. 2

Preoperative MRI (A, B, C) and pathological results (D) of a 22-year-old male patient with acute myeloid leukemia (AML). MRI indicates an abnormal nodular mass in the right temporal lobe (biopsy site) and left cerebellar hemisphere, with short T1 (A), long T2 (B), and homogeneous enhancement (C). Significant edema is observed in the surrounding brain tissue. Pathological results show proliferative lymphocytes in the brain tissue; some are arranged in perivascular lymphocytic cuffing structures. The cells exhibit atypia with dense growth of small tumor cells and frequent mitotic figures. Immunohistochemistry results: CD20 ( −), CD3 ( −), CD5 (a few +), MPO ( +), CD34 ( +), CD117 ( +), CD38 ( +), TdT ( −), and Ki-67 (70% +). MRI, Magnetic Resonance Imaging; MPO, Myeloperoxidase; TdT, Terminal Deoxynucleotidyl Transferase