Schizencephaly

KEY FACTS

IMAGING

• Transmantle gray matter (GM) lining clefts

○ Look for dimple in wall of ventricle if cleft is

narrow/closed

• Up to 1/2 of schizencephalies are bilateral

○ When bilateral, 60% are open-lipped on both sides

• GM lining clefts may appear hyperdense

• Ca++ when associated with CMV or COL4A1 mutations

• Prior to myelination, T2WI more clearly defines lesion

TOP DIFFERENTIAL DIAGNOSES

• Encephaloclastic porencephaly

○ Lined by gliotic white matter, not dysplastic GM

• Hydranencephaly

○ Residual tissue is supplied by posterior circulation

• Semilobar holoprosencephaly

○ Can mimic bilateral open-lip schizencephaly

PATHOLOGY

• Can be result of acquired in utero insult affecting neuronal

migration

• 1/3 of children with schizencephaly have non-CNS

abnormalities

• Infection (CMV), vascular insult, maternal trauma, toxin

CLINICAL ISSUES

• Unilateral: Seizures or mild motor deficit

• Bilateral: Developmental delay, paresis, microcephaly,

spasticity

• Seizure more common with unilateral clefts

• Size of clefts and presence of associated malformative

lesions govern severity of impairment

(Left) Coronal graphic shows

right closed-lip ﬈ and left

open-lip ﬊ schizencephaly,

both lined by gray matter.

Note absence of septum

pellucidum st. (Right) Coronal

T2FS MR shows bilateral

schizencephaly. A closed-lip

defect is seen on the right ﬇,

extending from the pial

surface to the ventricular

outpouching ſt, while a mildly

open-lip defect lined with

dysplastic gray matter is

present on the left st. Note

the abnormal vessels in the

left-sided schizencephalic cleft

﬊.