A fluid-filled sac (cyst) in the region below the cortex of the cerebrum. In magnetic resonance imaging, the fluid within the cyst has the same appearance as cerebrospinal fluid (CSF).
Comment:
Megalencephalic leukoencephalopathy with subcortical cysts is characterized by subcortical cysts that are present in the anterior temporal region most commonly and often in the frontoparietal region. Later, MRI may only reveal cerebral atrophy. The size and number of the cysts may increase over time. See Figure 1 of PMID:21977097.