Rounded minimally enhancing lesion within the lateral ventricle near the foramen of Munro with punctate areas of calcification. Marked hydrocephalus. 

A mass within the left lateral ventricle at the junction of the frontal horn and body demonstrates predominantly peripheral high T2 signal components that suppress on FLAIR, low-grade heterogeneous enhancement and has a broad contact/attachment to the left lateral margin of the septum pellucidum. Superiorly, strands of non-enhancing tissue that demonstrates susceptibility artefact. The lesion demonstrates high DWI signal with low ADC values of approximately 650 x 10-6mm2/s. The septum pellucidum is deviated to the right by up to 12 mm.

The lesion results in moderate obstruction of the lateral ventricles with associated periventricular T2/FLAIR hyperintensities suggestive of subependymal fluid spread. No appreciable direct intra-axial extension nor further intraventricular lesion. Non-enhancing T2/FLAIR white matter hyperintensities throughout the cerebral hemispheres are most compatible with changes of chronic small vessel ischemia.

Conclusion:

Intraventricular tumor with imaging features favoring a central neurocytoma (somewhat atypical in a patient of this age) or subependymoma. Other differentials for an intraventricular mass including an ependymoma or intraventricular metastasis are felt less likely given the imaging appearances.