Subependymal giant cell astrocytomas are benign (WHO grade I) tumors seen in patients with tuberous sclerosis. They are multilobulated and are found intraventricular near the foramen of Monro. As such they often present with a symptomatic obstruction hydrocephalus. 

Epidemiology

Subependymal giant cell astrocytomas are almost exclusively diagnosed in patients with tuberous sclerosis under the age of 20 and are rarely found in adulthood. Around 5-15% of patients with tuberous sclerosis develop these tumors. 

MRI features

T1: T1 imaging shows a heterogenous and hypo- to isointense signal compared to grey matter. 

T2: On T2 they are heterogenous and hyperintense to grey matter. The calcified components can be hypointense. 

T1 C+ (Gd): shows marked enhancement