PMC4392535_01
Axial fluid attenuation inversion recovery images obtained at presentation demonstrating a right-sided posterior thalamic mass lesion with hyperintensity and associated ventriculomegaly with periventricular hyperintensity suggestive of transependymal flow
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F1
Magnetic resonance imaging (MRI) without gadolinium enhancement showed a 1-cm mass in the pineal region and obstructive hydrocephalus [Figure 1].
Histopathological staining. (a) Reticulin stain; (b) PAS staining shows marked nuclear pleomorphism and isonucleosis. Note PAS-positive droplet (pink); (c) Ki-67 staining shows 3-5% proliferation; (d) Synaptophysin and neuron-specific enolase (NSE) staining reveals pleomorphic cells of neuronal origin
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F2
There was abundant positive staining with reticulin [Figure 2a] and rare periodic acid-Schiff (PAS)- and PAS-diastase (PAS-D)-positive droplets [Figure 2b]. Immunoperoxidase revealed strong staining for the neural markers neurofilament, neuron- specific enolase (NSE), synaptophysin, and glial markers including GFAP [Figure 2c]. The Ki-67 index was between 3% and 5% [Figure 2d].