Neuroradiology Board Review – Brain Tumors – Case 9
Neuroradiology brain tumor board review. This lecture is geared towards the ABR core exam for residents, but it would be useful for review for the ABR certifying exam or certificate of added qualification (CAQ) exam for neuroradiology.
More description and the answer (spoiler!) are seen below the video.
This case shows you some images from an axial head CT demonstrating a mass in the lateral ventricles near the septum pellucidum. On CT, it is somewhat heterogeneous. The MRI also shows a heterogeneous mass along the septum pellucidum which has some areas of avid enhancement and some areas of non-enhancement.
Anytime you have an intraventricular mass, you should be able to list a differential diagnosis, which includes:
- Meningioma
- Central neurocytoma (classic location along septum pellucidum)
- Subependymal giant cell tumor (associated with tuberous sclerosis)
- Ependymoma
- Subependymoma (usually doesn’t enhance)
- Choroid plexus tumors (both benign and malignant)
Then, the imaging features can help you favor one diagnosis over the other.
The diagnosis is: central neurocytoma
Central neurocytomas are classically masses along the anterior septum pellucidum near the foramen of Monro. They often look rather heterogenous both on T1, T2, and post-contrast T1. If you see a heterogeneous mass in the lateral ventricle in a testing scenario, it’s probably a central neurocytoma. The other lesions are possible and if you see any of the classical features of other lesions (such as a homogeneous and avidly enhancing mass that looks like a meningioma), you can consider other things.
This patient had a history of melanoma, but you can be pretty confident that this is not a melanoma metastasis because it lacks edema, has heterogeneous non-enhancing components, and has a classic appearance for central neurocytoma. They decided to manage this conservatively with imaging follow-up and it did not change with time, further corroborating the diagnosis.