Hamartomatous overgrowth of part or all of a hemisphere.
Broad featureless gyri with shallow sulci.
Abnormal primitive veins overlying shallow sulci.
Abnormal proliferation, migration and differentiation of neurons.
3% of cortical dysplasias
Associations: NF 1
Tuberous sclerosis
Klippel-Trenaunay-Weber syndrome
Proteus syndrome
Unilateral hypomelanosis of Ito
Epidermal nevus syndrome
Congenital infiltrating lipomatosis
Incontinentia pigmenti
Intractable seizures-progressive injury to good hemisphere.
Treatment: Surgical hemispherectomy( Figure)