case_images: PMC10629408_01
case_images: Brain MRI features: post contrast coronal (B), sagittal (C), and axial (E), T1-weighted sequences. See the obstructive hydrocephalus showing abnormally large lateral ventricles (yellow arrows on (B and C)), and the intra-axial mass located on cerebellar vermis with its solid and cystic components (red arrows on (A, B, C and E)). Cerebellar detail on axial apparent diffusion coefficient (ADC) map (F). Cervical spine MRI features: post contrast, sagittal T2 weighted sequences (A), and sagittal T1 weighted sequences (D). See the cerebellar mass and the multifocal spinal cord with leptomeningeal seeding (red arrows on (A and D)).
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case_images: The cystic component, on the lower part of the tumor, showed a T2 high signal intensity and T1 hypointense signal (Figure 1A-C and E). The mass caused obstructive hydrocephalus with significantly enlarged lateral ventricles (Figure 1B and C), obliteration of the cerebellopontine angle cistern, and tonsillar herniation. The diffusion-weighted magnetic resonance imaging (DW-MRI) as well as the apparent diffusion coefficient (ADC) map, did not show signal restriction on the solid component of the tumor (Figure 1F). Eight years later, a tumoral recurrence with supra and infratentorial involvement with multifocal spinal cord and leptomeningeal seeding was found on MRI (Figure 1A and D).
case_images: Histopathological, immunohistochemical, and molecular findings: stromal cells with clear to vacuolated cytoplasm and small round to oval nucleus intermingled with abundant delicate capillary vessels (A). Stromal cells show alpha-inhibin positivity (B). Capillary elements show VEGF positivity (C). MDM2 by IHC shows nuclear positivity in a high proportion of tumor cells (D), in accordance with the signal gains on MDM2 gene detected by FISH (E). EGFR by IHC shows membranous positivity in all tumor cells (F), also in accordance with the signal gains on EGFR gene detected by FISH (G).
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case_images: Inhibin alpha (Figure 2B), S100, neuron specific enolase (NSE), CD56, MDM2, and EGFR. Interestingly, PAX8 and Carbonic anhydrase IX (CaIX) were also positive. The vascular elements showed positivity for CD31, ERG, GLUT1, and VEGF (Figure 2C). The analysis of MDM2 and EGFR by fluorescent probes (FISH) revealed that 73% of stromal cells showed 5 copies (red and green signals) of MDM2 gene (12q15) (Figure 2E); 52% of stromal tumor cells showed 5 copies (red signals) of EGFR gene (7p11) but polysomies were also observed in 25% of stromal tumor cells (four green signals and two red signals) (Figure 2G).