Male, 60 years old, with hypertension and presyncope, brain cystic lesion seen on CT. A 9 mm nodule is evident within the anterior superior third ventricle situated at the level of the foramina of Monro. The nodule is isoattenuating relative to brain on T1 weighted images and hypoattenuating on T2 weighted images.The right lateral ventricle is significantly dilated with bowing of the septum pellucidum across the midline up to 10 mm. The left lateral ventricle is partially effaced by this encroachment from the right lateral ventricle. The third and fourth ventricles are normal in size.Mild T2 hyperintensity rimming both frontal horns is seen. A small area of T2 hyperintensity is evident in the right frontal subcortical white matter. Scattered T2 hyperintense lesions are evident within the left basal ganglia.Elsewhere, no significant focal parenchymal lesions or parenchymal edema is detected. No restricted diffusion is seen. No evidence to suggest acute intracranial hemorrhage.
Findings compatible with a third ventricular colloid cyst with associated obstruction of the right foramen of Monro and dilatation of the right lateral ventricle.Scattered T2 hyperintense foci may reflect areas of chronic ischemic injury. Lesions in the left basal ganglia could represent accommodation of chronic lacunar infarcts and/or dilated perivascular spaces.