case_images: PMC6481150_01
case_images: (a) Coronal T1 flair, postcontrast imaging 2 months prior to admission. No enhancing lesion seen. (b) Sagittal T1 flair, postcontrast imaging 2 months prior to admission. No enhancing lesion seen. (c) Coronal T1 flair, postcontrast imaging. There is a 1.7 x 2.5 x 1.8 cm homogenously enhancing mass with mild perilesional edema. (d) Sagittal T1 flair, postcontrast imaging. There is a 1.7 x 2.5 x 1.8 cm homogenously enhancing mass arising from the roof of the 4th ventricle invading into the cerebellar vermis.
case_images: CRIONM2019-2671794.001.jpg
case_images: PMC6481150_01_CRIONM2019-2671794.001.jpg
case_images: fig1
case_images: The patient underwent an MRI and magnetic resonance venography (MRV) upon seizure onset that revealed 2 areas of chronic hemorrhage but was otherwise unremarkable (Figure 1). An MRI showed a 2.5 x 1.8 x 1.7 cm homogenously enhancing mass that extended from the roof of the 4th ventricle (Figure 1).
case_images: Primary CNS lymphoma arising from the 4th ventricle. (a) Diffuse sheets of lymphoid tumor cells with focal necrosis, H&E stain, 40x magnification. (b) Large atypical tumor cells with angiocentric localization, H&E stain, 400x magnification. (c) CD20 immunostain, 400x magnification. (d) BCL-6 immunostain, 400x magnification. (e) MUM-1 immunostain, 400x magnification. (f) Ki-67 (MIB-1) immunostain (80% proliferation index), 400x magnification.
case_images: CRIONM2019-2671794.002.jpg
case_images: PMC6481150_01_CRIONM2019-2671794.002.jpg
case_images: fig2
case_images: Permanent sections confirmed the findings and highlighted the diffuse and angiocentric nature of the lymphoma, which was comprised primarily of large-sized lymphoma cells (Figure 2).
case_images: PET imaging of the brain showing increased uptake in the pituitary (a) and the posterior fossa (b). PET: positron emission tomography.
case_images: CRIONM2019-2671794.003.jpg
case_images: PMC6481150_01_CRIONM2019-2671794.003.jpg
case_images: fig3
case_images: Positron emission tomography (PET) indicated increased uptake (SUV of 19.3) in the 4th ventricular mass as well as a small focus of uptake in the right pituitary gland (Figure 3).