PMC9119690_01
Preoperative imaging studies and pathology.
. 
A: Computed tomography scan upon admission shows focal brain edema in the right frontal lobe.
. 
B: DWI of MRI demonstrates cortical and subcortical small high-signal lesions, and small enhanced-portions in Gd-T1W are identified (white arrows) corresponding to the high-signal lesions on DWI. High-signal areas are much wider on FLAIR, which are identified in multiple regions (white dotted arrows), including the right frontal lobe, right supplementary motor area, left central semiovale, and periventricular areas. ASL reveals low CBF in the right frontal lobe matching the high-signal areas on FLAIR.
. 
MRI: magnetic resonance image, DWI: diffusion-weighted image, FLAIR: fluid-attenuated inversion recovery, Gd-T1W: gadolinium-dimeglumin-T1-weighted image, ASL: arterial spin labeling.
. 
C: Histological investigations demonstrate cluster of large lymphocytes with CD20 strongly positive and CD10 weakly positive features. The MIB-1 index is higher than 50%.
2188-4226-9-0083-g001.jpg
PMC9119690_01_2188-4226-9-0083-g001.jpg
g001
Computed tomography (CT) of the brain revealed subcortical edema at the right frontal lobe, suggesting stroke or tumor (Fig. 1A). The diffusion-weighted image (DWI) of MRI revealed high signals at the cortex in the right frontal lobe, where the gadolinium dimeglumine T1-weighted image (Gd-T1W) showed small enhancements (Fig. 1B). FLAIR revealed multiple high-signal areas in both hemispheres, and arterial spin labeling (ASL) displayed a decrease in cerebral blood flow (CBF) in the right frontal (Fig. 1B). Diffuse large B-cell lymphoma (DLBCL) was histologically diagnosed by open biopsy in the enhanced lesion on MRI, where CD20 and CD10 were positive and the MIB-1 index was as high as 50% (Fig. 1C).
Follow-up MRI and histology in autopsy.
. 
A: MRI was performed 10 months after the treatment completion. High-signal areas in the right frontal lobe dramatically shrink on DWI and FLAIR, but periventricular high intensities enlarge on FLAIR with more obvious sulci, suggesting brain atrophy. There are no enhanced lesions on Gd-T1W, and ASL shows an increase in CBF without right-left difference.
. 
B: The brain tissue in autopsy displays no abnormalities macroanatomically, and the brain is incised in a coronal section along the black lines. The deep white matter in the right and left frontal lobes (a, b black squares) and right basal ganglia (c black square) are focally excised for histological staining.
. 
C: Histologically, scattered small clusters of lymphoma cells are found to be infiltrating into the brain parenchyma of both cerebral hemispheres and the right basal ganglia: (a) from the right frontal, (b) from the left frontal, (c) from the right putamen.
2188-4226-9-0083-g002.jpg
PMC9119690_01_2188-4226-9-0083-g002.jpg
g002
Ten months after the treatment, her MMSE score decreased to 11, and MRI revealed progression of brain atrophy with enlarged ventricle and clearer sulci (Fig. 2A). No enhancement was identified, and an increase in CBF was symmetrically recognized in ASL (Fig. 2A). Autopsy was performed, and the brain seemed to be normal macroanatomically (Fig. 2B). However, histological investigation confirmed several small clusters of malignant lymphoma cells scattered in the brain parenchyma (Fig. 2C).