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Fig. 6 | Insights into Imaging

Fig. 6

From: Posterior fossa extra-axial variations of medulloblastoma: a pictorial review as a primer for radiologists

Fig. 6Fig. 6

A A 17-year-old male suspected of having an intracranial tumor. Brain CT without (a) and with contrast medium (b–d). A left-sided, well-defined, large, hyperdense lateral cerebellar mass (asterisks) with diffuse homogenous enhancement with contrast medium (b–d) exerts mass effect on the fourth ventricle (white arrowheads), cerebellum (black arrowheads), and brain stem (benched arrows). It also causes ballooning of the temporal horns of the lateral ventricles, indicating obstructive hydrocephalus. CT computed tomography. B Brain MRI without and with intravenous contrast medium. A well-defined mass centered in the lateral cerebellar region (asterisks) is observed, showing hypointense signal on T1-weighted imaging (a) and hyperintense signal on T2-weighted imaging (b). Post-contrast images demonstrate diffuse heterogeneous enhancement (c, d) with restricted diffusion (e, f). The mass causes buckling of the cerebellar parenchyma, folia (white arrowheads). Moreover, a rim of cerebrospinal fluid cleft at the periphery denotes extra-axial localization (black arrowhead; b). It has a mass effect on the brain stem, contralateral cerebellar hemisphere, and fourth ventricle (arrow), resulting in obstructive hydrocephalus. Additionally, it exerts a mass effect over the ipsilateral dural venous sinus system (benched arrows). The neuroaxis imaging finding was unremarkable (not shown). C Proton magnetic resonance spectroscopy analysis (single-voxel technique). A prominent choline peak, a high choline/creatinine ratio, and a decreased NAA peak are observed. The taurine peak is not evident at 3.25 or 3.43 ppm. D Post-surgery histopathological analysis at various magnifications. (a) Hematoxylin and eosin staining show classic nodular tumor cells. Small basophilic tumor cells exhibit diffuse growth and are arranged in trabeculae, sheets, and nests. (b) The tumor cells have round or oval nuclei with deeply stained chromatin and a high nuclear-cytoplasmic ratio with mitotic figures and partial necrosis. The final diagnosis is medulloblastoma of a nodular desmoplastic type (WHO grade IV). WHO World Health Organization

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