See the first aid entry on Tuberous sclerosis. It is associated with increased incidence of subependymal giant cell astrocytoma and many other conditions.
Tuberous sclerosis = "ash-leaf spots" = oval-shaped areas pale areas on skin.
often d/t hamartomas
This pretty much answers 3-4 of the mnemonic for tuberous sclerosis: "HAMARTOMASS"
H-amartomas in CNS and skin/
A-sh leaf spots (hypopigmented macule) /
M-mental retardation /
S-hagreen patches /