NEUROPATHOLOGY II MALFORMATIONS OF THE CNS. MALFORMATIONS OF THE CNS. DEFINITIONS. DEFINITIONS. *Malformations *Malformations - - primary disturbance of embryonic or primary disturbance of embryonic or fetal development fetal development *Field defect *Field defect *Disruption *Disruption -secondary compromise of development -secondary compromise of development due to vascular events, infections, etc. due to vascular events, infections, etc.
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NEUROPATHOLOGY II MALFORMATIONS OF THE CNS. DEFINITIONS. *Malformations -primary disturbance of embryonic or fetal development *Field defect *Disruption.
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NEUROPATHOLOGY II
MALFORMATIONS OF THE CNS. MALFORMATIONS OF THE CNS. DEFINITIONS. DEFINITIONS. *Malformations *Malformations -primary disturbance -primary disturbance of embryonic or of embryonic or fetal development fetal development *Field defect *Field defect *Disruption *Disruption --secondary compromise of development secondary compromise of development due to vascular events, infections, etc. due to vascular events, infections, etc.
NEUROPATHOLOGY II
DEFINITIONS.... DEFINITIONS.... *Deformation *Deformation -external mechanical influences -external mechanical influences affect affect ing development ing development *Dysplasia *Dysplasia --abnormal neuronal clustering/localiza abnormal neuronal clustering/localiza tion secondary to neuronal tion secondary to neuronal migrational migrational defects defects
-Warfarin-Warfarinmicrocephaly, meningocele, microcephaly, meningocele, Dandy-Walker malf.,agenesis of corpus Dandy-Walker malf.,agenesis of corpus
callosum and diffuse cerebral atrophy callosum and diffuse cerebral atrophy
NEUROPATHOLOGY II
CAUSES OF MALFORMATIONS... CAUSES OF MALFORMATIONS... *Alcohol *Alcohol -Fetal-alcohol syndrome -Fetal-alcohol syndrome 0.4-3.5/live births 0.4-3.5/live births 190/1000 in some North American 190/1000 in some North American
Indian pop.(genetic? poverty?) Indian pop.(genetic? poverty?) Neonatal mortality-5.8-17% Neonatal mortality-5.8-17% Microcephaly,microphtalmia,mental re Microcephaly,microphtalmia,mental re tardation,hyperactivity,motor problems tardation,hyperactivity,motor problems Growth deficiency(often Growth deficiency(often below 10th below 10th percentile) percentile)
NEUROPATHOLOGY II
CAUSES OF MALFORMATIONS... CAUSES OF MALFORMATIONS...
*Cocaine *Cocaine -Myelomeningocele, -Myelomeningocele, encephalocele, encephalocele, agenesis of corpus agenesis of corpus callosum,hetero callosum,hetero
topias, schizencephaly, etc. topias, schizencephaly, etc.
NEUROPATHOLOGY II
MAJOR GROUPS OF MALFORM.... MAJOR GROUPS OF MALFORM....
NEURAL TUBE DEFECTS(Dysraphic disorders) NEURAL TUBE DEFECTS(Dysraphic disorders) *Primary *Primary defects in closure of neuropore defects in closure of neuropore -Anencephaly -Anencephaly -Craniorachischisis -Craniorachischisis -Myelomeningocele -Myelomeningocele *Primary bone defects(abnormality in axial *Primary bone defects(abnormality in axial mesoderm development) mesoderm development) -Spina bifida occulta -Spina bifida occulta -Encephalocele -Encephalocele -Meningocele-Meningocele
NEUROPATHOLOGY II
ANENCEPHALYANENCEPHALY*Is the MOST common congenital malfor *Is the MOST common congenital malfor mation of the brain mation of the brain*Known as far back as Egyptian antiquity*Known as far back as Egyptian antiquity*Compared to the toad(Morgagni,1761)*Compared to the toad(Morgagni,1761)*Geographic variation in incidence: *Geographic variation in incidence: -1-6 / 1000 in Ireland -1-6 / 1000 in Ireland and Wales and Wales -0.5--0.5-2 / 1000 in US2 / 1000 in US
NEUROPATHOLOGY II
ANENCEPHALY... ANENCEPHALY... *Etiology – unknown *Etiology – unknown *Possible risk factors: *Possible risk factors: -Geographic location -Geographic location -Socioeconomic -Socioeconomic factors factors -Diet -Diet folic acid deficiency folic acid deficiency --GeneticGenetic few familial cases observed few familial cases observed *More common in females *More common in females
NEUROPATHOLOGY II
ANENCEPHALY.... ANENCEPHALY.... -Hypoplasia or absence of cranium -Hypoplasia or absence of cranium -Shallow orbits with protrusion of eyes -Shallow orbits with protrusion of eyes -Hypoplastic lungs -Hypoplastic lungs -Large thymus -Large thymus -Abnormal pituitary(lack of -Abnormal pituitary(lack of hypothalamus/ hypothalamus/ neurohypophysis) neurohypophysis) -Other abnormalities: adrenal hypoplasia -Other abnormalities: adrenal hypoplasia
MYELOMENINGOCELE. MYELOMENINGOCELE. *Herniation of both meninges/spinal cord through a *Herniation of both meninges/spinal cord through a large vertebral defect *Most large vertebral defect *Most often lumbosacral often lumbosacral *Frequent association w/hydrocephalus *Frequent association w/hydrocephalus -Arnold-Chiari malformation type II -Arnold-Chiari malformation type II *Area medullovasculosa *Area medullovasculosa *Meningocele: herniation *Meningocele: herniation of meninges only *Occult of meninges only *Occult spina bifida:mildest form of neural tube defectspina bifida:mildest form of neural tube defect
NEUROPATHOLOGY II
SPINAL DYSRAPHISM(spina bifida). SPINAL DYSRAPHISM(spina bifida). *It may be an asymptomatic bone *It may be an asymptomatic bone defect (spina bifida defect (spina bifida occulta) occulta) *Also, it can be a severe malformation w/ *Also, it can be a severe malformation w/ flattened and flattened and disorganized segment of spinal cord disorganized segment of spinal cord associated to an outpouching of meningesassociated to an outpouching of meninges
NEUROPATHOLOGY II
ARNOLD-CHIARI MALFORMATION. ARNOLD-CHIARI MALFORMATION. There are 4 types: There are 4 types: *Type I –cerebellar tonsillar herniation *Type I –cerebellar tonsillar herniation *Type II- malformation of craniobasal *Type II- malformation of craniobasal bone, bone, shallow posterior shallow posterior fossa *Type III-fossa *Type III-occipito-cervical bony defect occipito-cervical bony defect
-occipital encephalocele -occipital encephalocele -herniation of cerebellum into en -herniation of cerebellum into en
ARNOLD-CHIARI MALFORMATION... ARNOLD-CHIARI MALFORMATION... *TYPE II *TYPE II -Herniation of inferior cerebellar -Herniation of inferior cerebellar vermis -Elongation and vermis -Elongation and downward displacement of downward displacement of medulla and cervical cord medulla and cervical cord -Malformation of craniobasal bone, -Malformation of craniobasal bone, shallow posterior fossashallow posterior fossa
NEUROPATHOLOGY II
ARNOLD-CHIARI MALFORMATION... ARNOLD-CHIARI MALFORMATION... *Associated hydrocephalus, *Associated hydrocephalus, meningomyelo cele, aqueductal meningomyelo cele, aqueductal stenosis or atresia, ventri cular stenosis or atresia, ventri cular neuronal heterotopia, microgyria, neuronal heterotopia, microgyria, “beaking” of tectum “beaking” of tectum *Craniolacunae – single or multiple translu *Craniolacunae – single or multiple translu cent thinning of cranium – dissapears cent thinning of cranium – dissapears at age of 1-2 yrs. at age of 1-2 yrs.
NEUROPATHOLOGY II
SYRINGOMYELIA. SYRINGOMYELIA. *About 90% of cases associated w/Arnold- *About 90% of cases associated w/Arnold- Chiari type I malformation(tonsillar Chiari type I malformation(tonsillar herniat.) *Wasting and weakness herniat.) *Wasting and weakness of hand and fore- arm of hand and fore- arm muscles, dissociated anesthesia of upper limbs muscles, dissociated anesthesia of upper limbs *Kyphoscoliosis or Charcot´s joints *Kyphoscoliosis or Charcot´s joints *Slowly progressive *Slowly progressive *Syringobulbia may be present *Syringobulbia may be present
NEUROPATHOLOGY II
SYRINGOMYELIA.... SYRINGOMYELIA.... *Characterized by formation of a fluid- *Characterized by formation of a fluid-filled cleft-like cavity in the inner cord filled cleft-like cavity in the inner cord *Lesion associated *Lesion associated w/destruction of gray and white matter in the w/destruction of gray and white matter in the vacinity, surrounded by a dense reactive vacinity, surrounded by a dense reactive gliosis *The gliosis *The formed cavity may be extended from the formed cavity may be extended from the cervical spinal cord upward into the brainstemcervical spinal cord upward into the brainstem
DISORDERS OF FOREBRAIN INDUCT. DISORDERS OF FOREBRAIN INDUCT. *Holoprosencephaly. *Holoprosencephaly.
-Anomalies of prosencephalic outgrowth -Anomalies of prosencephalic outgrowth and cleavage and cleavage
-Types – classified by degree of gyral de -Types – classified by degree of gyral de velopment:velopment:
AlobarAlobarSemilobarSemilobarLobarLobar
NEUROPATHOLOGY II
DISORDERS OF FOREBRAIN INDUCT... DISORDERS OF FOREBRAIN INDUCT... *Holoprosencephaly.... *Holoprosencephaly....
-Varying grades of facial dysmorphim: -Varying grades of facial dysmorphim: “the face predicts the brain” “the face predicts the brain” -Other systemic malformations are -Other systemic malformations are freq. freq. -Mild form of these is -Mild form of these is known as arrhinen known as arrhinen
cephaly w/lack of development of the cephaly w/lack of development of the olfactory bulb and tract olfactory bulb and tract
NEUROPATHOLOGY II
DISORDERS OF FOREBRAIN INDUCT... DISORDERS OF FOREBRAIN INDUCT... *Holoprosencephaly....*Holoprosencephaly....
Trisomy 13(most common), 18, etcTrisomy 13(most common), 18, etcFamilial: AR or AD or X-linked RFamilial: AR or AD or X-linked RMaternal diabetesMaternal diabetesMaternal infections:toxoplasma,rubellaMaternal infections:toxoplasma,rubellaFetal-alcohol syndromeFetal-alcohol syndrome
-Defects in the wall of the cerebral he -Defects in the wall of the cerebral he misphere with communication misphere with communication between between ventricle and the surface ventricle and the surface
-”Basket brain”(Schizencephaly) w/seve -”Basket brain”(Schizencephaly) w/seve re bilateral hemispheric re bilateral hemispheric porencephalic porencephalic
defectsdefectssmooth walled and surrounded smooth walled and surrounded by gyral pattern by gyral pattern
-Spasticity-Spasticity-Seizures-Seizures-Severe mental retardation-Severe mental retardation-Blindness-Blindness-Survival into adult life in some patients-Survival into adult life in some patients
NEUROPATHOLOGY II ““Basket brain”(Schizencephaly) Basket brain”(Schizencephaly)
*Etiology – unknown *Etiology – unknown -Presumably destructive events -Presumably destructive events occurring early during fetal lifeoccurring early during fetal life
-Events antedate the acquisition of mature -Events antedate the acquisition of mature astroglial response or completion of astroglial response or completion of convo- lutional convo- lutional developmentdevelopment-Vascular insults, infections, trauma, etc.-Vascular insults, infections, trauma, etc.
Seizures,spascity,poor psychomotor Seizures,spascity,poor psychomotor development development
Survival is short but can be up to 1 yr or Survival is short but can be up to 1 yr or longer longer
NEUROPATHOLOGY II
ENCEP-HALOCLASTIC DEFECTS...ENCEP-HALOCLASTIC DEFECTS...*Agenesis of corpus callosum.*Agenesis of corpus callosum.
-Relatively a common malformation(1 -Relatively a common malformation(1 in 19,000 autopsies and 2.3% in chil in 19,000 autopsies and 2.3% in chil
dren w/mental retardation) dren w/mental retardation)-Defect that can be partial or complete-Defect that can be partial or complete-May present seizures, intellectual im- -May present seizures, intellectual im-
pairment, psychosis(due mostly to pairment, psychosis(due mostly to otherother
Encephloclastic mechanism as in porencephaly Encephloclastic mechanism as in porencephaly and hydranencephaly and hydranencephaly
-Mainly related to vascular events ocurring -Mainly related to vascular events ocurring in in the third trimester or perinatal life the third trimester or perinatal life
-Severe forms are due to global hemispheric -Severe forms are due to global hemispheric necrosis necrosis -May -May also follow viral infectionsalso follow viral infections
*Multicystic encephalomalacia...*Multicystic encephalomalacia... -Are cavities ragged and irregular without -Are cavities ragged and irregular without cortical malformations cortical malformations-Gliosis and lipid laden macrophages are his -Gliosis and lipid laden macrophages are his tological characteristics tological characteristics