PMC9699877_01
The tumor showed slightly high density on CT (a), slightly hypointensity on T1-weighted image (b), iso- to slightly high intensity on a T2-weighted image (c), uniformly high intensity on diffusion-weighted image (d), and heterogeneous enhancement with gadolinium (e: axial, f: sagittal, and g: coronal).
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F1
Computed tomography (CT) showed a slightly high-density tumor [Figure 1a] that was seen in the fourth ventricle on magnetic resonance imaging (MRI), along with obstructive hydrocephalus. T1-weighted imaging [Figure 1b] and iso- to slightly hyperintense on T2-weighted imaging [Figure 1c]. The tumor was uniformly hyperintense on diffusion-weighted imaging [Figure 1d] and iso- to slightly hyperintense on apparent diffusion coefficient. After injection of gadolinium-based contrast medium, the tumor showed uniform contrast enhancement [Figures 1e-g].
Histopathological examination revealed diffusely growing tumor cells with a high nucleocytoplasmic ratio and differently sized nuclei, some of which had mucus, and multiple mitotic figures (a). The tumor was negative for CD10 (b) and was positive for CD20 (c), CD79a (d), Bcl-6 (e), and MUM-1 (f). a: Hematoxylin-eosin staining, x200, b: CD10, x400, c: CD20, x400, d: CD79a, x400, e: Bcl-6, x400, and f: MUM-1, x400.
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F2
Histopathological examination revealed diffusely growing tumor cells with a high nucleocytoplasmic ratio and differently sized nuclei, some of which had mucus and multiple mitotic figures [Figure 2a]. The tumor was negative for CD3, CD5, CD10, Keratin7, and Keratin20 and was positive for CD20, CD79a, Bcl-2, Bcl-6, and MUM-1 [Figures 2b-f].
The tumor decreased in size but the obstructive hydrocephalus remained after 5 cycles of R-MPV regimen (a: axial and b: sagittal). The patient achieved complete response after chemotherapy with autologous peripheral blood stem cell transplantation. There was no sign of recurrence at 20 months after biopsy (c: axial and d: sagittal).
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F3
After 5 cycles of R-MPV regimen, the tumor decreased in size but the obstructive hydrocephalus remained [Figures 3a and b]. There was no sign of recurrence at 20 months after biopsy [Figures 3c and d].