PMC3606961_01
Sagittal contrast-enhanced T1-weighted (a) and axial T2-weighted (b) images showing cystic cerebellar mass (asterisk) with a large dyshomogeneous enhancing nodule (white arrows) arising from the left cerebellar hemisphere.
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PMC3606961_01_1129-2377-14-3-1.jpg
F1
Considering the atypical headache pattern, the episode of vomiting without headache and the paroxysmal torticollis, he underwent a brain magnetic resonance imaging (MRI) that showed a cerebellar expansive lesion (Figure 1) and a triventricular hydrocephalus.
PMC3606961_02
Sagittal contrast-enhanced T1-weighted (a) showing a caudal protrusion (12 mm) of the elongated triangular-shaped tonsils below the foramen magnum (white arrows). Axial T1-weighted image (b) confirms cerebellar tonsils filling the foramen magnum and effacing the cysterna magna (white arrows).
1129-2377-14-3-2.jpg
PMC3606961_02_1129-2377-14-3-2.jpg
F2
A brain MRI (26 months) showed the herniation of the cerebellar tonsils (12 mm) through the foramen magnum until the second cervical vertebra, consistent with a CM1 (Figure 2).