Well-defined lobulated midline cystic mass occupying the pineal region. It appears hyperintense on T2WI, hypointense on T1WI, demonstrating incomplete suppression on FLAIR. This lesion extends into the third ventricle superiorly, resulting in mild third ventricular dilatation, but no gross hydrocephalus. It extends posteriorly into the quadrigeminal cistern, best seen on the sagittal images of this study. The adjacent pineal gland and tectal plate are intact, with minimal narrowing of the cranial portion of the cerebral aqueduct of Sylvius.
On DWI, this lesion appears of a heterogeneously high signal, corresponding to ADC values similar to brain parenchyma.
No definite susceptibility artefact on SWI to suggest intralesional calcifications.
Enhancing perilesional vascular structures on the postcontrast study. No enhancing solid components.