A pineal cyst is demonstrated measuring 12 x 8 x 11 mm with a thin (less than 1 mm) enhancing rim and a thin septum on the left side, but no nodule or solid component. It minimally distorts the tectal plate, without hydrocephalus. Flow void in the aqueduct is visible. Phase contrast imaging (SWI) confirms the presence of peripherally located calcification (on phase imaging the peripherally located calcium is black (opposite to blood in veins), thus enabling you to distinguish Ca+ from blood product).
The remainder of the brain is unremarkable in appearance with no intra extra-axial masses or regions of abnormal contrast enhancement.
The features are those of a pineal cyst. Although almost certainly does not represent a cystic pineal tumour, given the enhancing septum and prominent size a repeat scan in 12 months time to ensure stability is probably warranted.