Presentation
Seizures and low IQ.
Patient Data
Characteristic features of tuberous sclerosis are demonstrated including high T2 regions consistent with cortical and subcortical tubers, and two punctate regions of susceptibility induced signal loss along the ependymal border of the left lateral ventricle consistent with calcified subependymal nodules. The anterior of the two is located adjacent to the foramen of Monro and demonstrates contrast enhancement, but only measures 2 mm in size. A prominent radial band extends from the frontal horn of the lateral ventricle to the middle frontal gyrus cortex, and this demonstrates enhancement also, an uncommon but well recognized feature.
Incidental note is made of a small extra axial CSF intensity region adjacent to the right frontal lobe, remodeling the overlying skull consistent with a small arachnoid cyst. The brain is otherwise unremarkable in appearance, with normal ventricular size.
Conclusion:
Characteristic features of tuberous sclerosis with only a very small (2 mm) enhancing subependymal nodule near the left foramen of Munro. Enhancement is seen in subependymal tubers and without increasing size, is not suggestive of a subependymal giant cell astrocytoma.
Case Discussion
Radial bands are specific for the diagnosis of tuberous sclerosis and are usually best seen on T2 / FLAIR as linear regions of high signal extending form the ventricle to the cortex. In a minority of cases they can enhance, as is seen in this case (best seen on coronal images).