Subependymal giant cell astrocytoma
A subependymal giant cell astrocytoma (SGCA) is a benign (WHO grade I 4) astrocytoma and is seen with increased incidence in tuberous sclerosis (TS).
SGCA's are a well known manifestation of TS and affects 5 - 15% of patients with the condition.
Location
The foramen of Monroe is the classic location. Some of the subependymal nodules themselves can transform into SGCA over a period of time.
Demographics and clinical presentation
They principally affect patients under 20, but are occasionally found in older people. Symptoms are usually a result of obstructive hydrocephalus because of mass effect around the ventricular system, commonly the interventricular foramen (of Monro), the cerebral aqueduct (of Sylvius) or the third or fourth ventricles.
Young children who have tuberous sclerosis may be offered screening becuase of the increased risk of developing subependymal giant cell astrocytomas
Radiographic features
CT
Typically appears as an intraventricular mass near the foramen of Monro. Iso attenuating to slightly hypoattenuating to grey matter. Calcification is common and haemorrhage is possible. Often shows marked contrast enhancement (differentiating feature from sub ependymal nodule)
MRI
- T1 : heterogenous and hypo to iso intense to grey matter
- T2 : heterogenous and hyper intense to grey matter ; calcific components can be hypo intense
- C+ (GAD) : shows marked enhancement
Treatment
The main treatment is surgical removal and is usually curative. Oral rapamycin (sirolimus) has also been trialled 3.
