Congenital Lesions In The Brain

Front 1

Septo-optic dysplasia

Back 1

Hypoplasia of the optic nerves with complete or partial abscence of the septum pellucidum.
Endocrine abnormalities are common (related to hypothamalic-pituitary axis abnormalities with reduction in growth hormone) and migrational anomalies and perventricular cysts are also seen.

Front 2

Alobar holoprosencephaly

Back 2

consistening of an anterior rind of brain tissue and a monoventricle, which communicates with a dorsal cyst.
The thalami are fused and the septum pellucidum, corpus callosum and falx are absent.
Need to discriminate from hydranencephaly and severe hydrocephalus.

Front 3

Semilobar holoprosencephaly.

Back 3

Less severe and shows partial fusion of the hemispheres.
Corpus and septum pellucidum are absent or dysgenic.
High association with migrational anomalies.
Posterior portion of the interhemispheric fissure and falx are usually formed.

Front 4

lobar holoprosencephaly.

Back 4

Relatively normal appearing brain.
Partial absence of a frontal interhemispheric fissure.
Absent septum pellucidum. Body and splenium of the corpus are usually present with the genu and rostrum absent.

Hint 4

Abscence of septum is constant helpful feature of the holoprosencephalies.

Front 5

Agenesis of the corpus callosum

Back 5

Forms from front to back and myelinates from back to front. Partial agenesis will result in formation of the genu and anterior body but absence of the posterior body and splenium.
Secondary destruction of the corpus and holoprosencephaly can result in nonsequential segments of absent callosum.
"Steer horn" apperance of the lateral ventricles on coronal.
"race car" configuration of ventricles on axial.

Front 6

Lipoma of the corpus callosum

Back 6

Show high T1 signal which supresses with the use of fat saturation imaging.
Do not cause mass effect and vessels course through lese lessions unperturbed.
Occasionally associated with callosal anomalies.

Front 7

Cephaloceles

Back 7

Failure of the skull and dura to close over the brain, leading to a herniation of intracranial contents through the defect.
Meningoceles reflect herniation of the leptomeninges alone, while encephaloceles are associated with herniation of brain and leptomeninges.
Occipital encephaloceles are the most common.

Front 8

Lissencephaly/agyria

Back 8

Absence of gyri
Lack of sulcation gives a smooth hourglass appearance to the brain. Cortex is abnormally thickened and multilayered.
Pattern of arrested neuronal migration in which only four cortical layers are present with band heterotopias.

Front 9

polymicrogyria and pachygria

Back 9

polymicrogyria: cortical dysplasia. Thick mantle of gray matter with multiple small gyri. Underlying white matter gliosis can help differentiate.
Pachygria is incomplete lissencephaly.
In both the normal interdigitating fingers of subcortical white matter are absent.
Produce an abnormally thickened cortex with little or no sulcation, but in distinction to lissencephaly, they are more focal.
Also show anomalous cortical venous drainage.