Presentation
Slow change in cognition.
Patient Data
Low density intraventricular mass in the region of the foramen of Monroe. Left lateral ventricle is dilated.
No appreciable enhancement of the intraventricular mass.
Non-enhancing, well-defined, T1 hypointense / T2 hyperintense mass within the left lateral ventricle, in contact with the septum pellucidum and in the region of the foramen of Monro. No diffusion restriction. Dilatation of the left lateral ventricle.
Histopathology:
MICROSCOPIC DESCRIPTION: Sections show a paucicellular glial tumor with extensive microcystic change. Glial cells form small clusters and aggregates set within a fibrillary background. No necrosis or mitoses are seen. No brain parenchyma is included within the specimen submitted.
DIAGNOSIS: Brain lesion: Subependymoma, WHO grade I.
Case Discussion
This mass has a broad attachment to the septum pellucidum, and this helps narrow the long list of intraventricular masses to (mainly): subependymoma, subependymal giant cell astrocytoma, central neurocytoma and ependymoma. The best clue to determine this is a subependymoma is the lack of enhancement.