A pineal region mass demonstrates heterogeneous contrast enhancement and intermediate T2 signal. Diffusion weighted imaging demonstrates reduced ADC values (approximately 600 x 10-6 mm2/s) suggesting high cellularity. It is definitely separate from the tectum which it distorts and compresses without complete obliteration of the aqueduct. Attenuated flow void is seen in the aqueduct, and although no overt obstructive hydrocephalus is yet present, there is some distension of the recesses of the third ventricle.
Review of prior CT demonstrates the calcification of the pineal gland to be located peripherally around the mass, rather than engulfed. The remainder of the brain is unremarkable in appearance.
Conclusion:
Appearances most likely represents a pineal parenchymal tumour, with high cellularity worrisome for a higher grade despite the well-circumscribed appearance (pineal parenchymal tumour of intermediate differentiation (WHO II or III). Pattern of displacement of calcium, gender, and low ADC values make a germ cell tumour less likely.