case_images: PMC11743571_01
case_images: MRI findings on initial admission. T1-weighted and T2-weighted images, respectively, show slightly prolonged signal intensity in the left temporal lobe, thalamus, and basal ganglia regions (A, B). Fluid-attenuated inversion recovery (FLAIR) sequence reveals high signal intensity in the same regions (C). Apparent diffusion coefficient (ADC) map demonstrates mildly elevated signal intensity (D). Contrast-enhanced T1-weighted image shows focal areas of speckled and striated enhancement within the left temporal lobe, thalamus, and basal ganglia (E). Arterial spin labeling (ASL) perfusion map reveals increased perfusion in the corresponding areas of abnormal signal intensity (F).
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case_images: MRI without contrast revealed hyperintensity in the left midbrain and pons, with abnormal signals in the adjacent left pontine tegmentum, temporal lobe, thalamus, and basal ganglia ( Figure 1 ).
case_images: MRI at second admission. T1-weighted and T2-weighted images, respectively, demonstrating multifocal hyperintensities within the left temporal lobe, thalamus, and basal ganglia regions. The lesions appear larger compared to the previous MRI (A, B). Fluid-attenuated inversion recovery (FLAIR) and diffusion-weighted imaging (DWI) sequences reveal high signal intensities in the lesions, with surrounding areas exhibiting extensive T1 and T2 hyperintensity (C, D). Apparent diffusion coefficient (ADC) map shows restricted diffusion within the lesions, indicated by high signal intensity (E). Contrast-enhanced T1-weighted image demonstrates significant enhancement of the lesions, with a possible "umbilical notch sign"(arrow) (F). Magnetic resonance spectroscopy (MRS) reveals a significant decrease in N-acetyl aspartate (NAA) peak and a corresponding increase in choline (Cho) peak within the lesion area, suggestive of a neoplastic process (G).
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case_images: f2
case_images: The findings suggested a neoplastic process, possibly lymphoma, although inflammatory granulomatous lesions could not be entirely ruled out ( Figure 2 ). Magnetic resonance spectroscopy (MRS) further supported the possibility of a neoplastic lesion, likely a large B-cell lymphoma ( Figure 2 ).
case_images: Histopathologic examination of the occipital lobe with PCNSL. Microscopic examination (hematoxylin and eosin stain) revealed infiltration of brain tissue by tumor cells (A, x100). These cells displayed enlarged nuclei with prominent nucleoli, scant cytoplasm, and a relatively uniform appearance. The nuclei exhibited a deep staining pattern with coarse chromatin and readily identifiable mitotic figures (B,x400). Immunohistochemical analysis demonstrated diffuse positivity for PAX5 (C, x200), indicating B-cell lineage. The proliferation rate, as assessed by Ki-67 staining, was high, with approximately 80% of tumor cells expressing this marker (D, x200). BCL6, a protein associated with non-germinal center B-cells, was predominantly expressed by the tumor cells (E, x200). GFAP, a marker for glial cells, was negative within the tumor cells, while positive staining was observed in the surrounding residual brain tissue (F, x200). Additionally, the tumor cells were strongly positive for CD20 (B-cell marker) (G, x200), negative for CD3 (T-cell marker) (H, x200), diffusely positive for CD79a (B-cell marker) (I, x200), and mostly positive for MUM1 (another B-cell marker) (J, x200).
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case_images: f3
case_images: Pathological examination of the right occipital lobe lesion ( Figure 3 ) demonstrated clusters of small to medium-sized round tumor cells with prominent nuclei within the brain tissue, exhibiting a focal perivascular growth pattern, Immunohistochemistry analysis revealed the following profile: CD20 (diffuse+), CD79a (diffuse+), Pax-5 (+), MUM1 (diffuse+), BCL-2 (weakly positive in some cells), BCL-6 (mostly positive), CD10 (-), CD3 (-), CD5 (-), CD23 (-), CD138 (-), ALK (-), CD15 (-), CD30 (-), CyclinD1(-), MYC(+), Ki-67(high expression, approximately 80%+), Vimentin (+), EMA (-), CK-pan (-), CgA (-), SYN (-), CD56 (-), SMA (-), Desmin (-), MyOD1 (-), Myoglobin (paranuclear punctate+).