Central Neurocytoma

Central neurocytomas are intraventricular neuroepithelial tumors that characteristically present as bubbly, lobulated masses in the frontal horn or body of the lateral ventricles attached to the septum pellucidum. They account for about half of all intraventricular masses in patients between the ages of 20-40 years.

On CT, central neurocytomas have mixed solid and cystic components and calcifications in up to 70% of cases. The lesions are highly vascular and may be complicated by hemorrhage, but this is rare. There is moderate, heterogeneous enhancement. Hydrocephalus may be seen with obstruction of the foramina of Monro.

MRI similarly shows a heterogeneous mass with cystic and solid components. Flow voids and calcifications present as low-signal areas. The lesion is predominantly hyperintense on FLAIR sequences. Post contrast images show heterogeneous, moderate enhancement.

The lesions are typically low metabolism on FDG-PET.

Differential considerations include:

• Subependymoma: May have a similar appearance. More commonly in the 4th ventricle. Enhancement is usually weaker.
• Choroid plexus papilloma: Intense enhancement. Found in the lateral ventricles in younger patients. More common in the 4th ventricle in older patients.
• Metastasis: Look for primary, other lesions.
• Meningioma: Well defined mass with intense enhancement. Typical location is the trigone of the lateral ventricles and is seen in older patients.
• Subependymal giant cell astrocytoma: Seen with tuberous sclerosis.
• Ependymoma: Rare for a supratentorial ependymoma to be intraventricular. Has much more aggressive appearance.