Glossary in Congenital Malformations
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#Camptodactyly: Means permenant flexion of one or more fingers. (Campto-
means flex).
#Cavum septi pellucidi and
cavum Vergae: As the corpus callosum grows,
the banks of the median groove ventral to the callosum separate to form a small
pocket that develops into the cavum septum pellucidi (also kown as 5th
ventricle), a space that persists until term and that gradually narrows to a
potential space in the adult. Persistence of the cavum septi pellucidi, and its
posterior extension the cavum vergae are not malformations. The cavum septi
pellucidi and cavum vergae should not be communicating with the ventricles.
#Cephalocele
(encephalocele): a
herniation of cranial contents through a skull defect.
#Cerebellar dysplasia: I prefer to limit this term to abnormal formation
of the cerebellar gyri and/or dentate nuclei in order to distinguish this entity
from cerebellar heterotopia. The hemispheres are preferentially affected.
#Cerebellar
Dysplasia: [according to Rorke et al., 1968]
·
Compact groups of mature neurons: Can be found in 58% of normal fetus, according to
Rorke et al.
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Focal and perivascular immature granular cell
collections: They are nests of primitive looking cells that
frequently arrange around blood vessels. They are found in about 25% of all
cases but they should not be seen after the 4th postnatal month.
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Heterotaxias:
Poorly organized mixed cell rests.
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Heterotopias: Well-organized
cell rests composed of all components of cerebellar arrayed in normal
relationships. Heterotopias are much less common than heterotaxias.
·
Heterotopias and heterotaxias are associated with trisomy 13 and to a lesser
extent trisomy 18. They are also associated with encephalocele.
#Cerebellar hemispheric
(lateral) aplasia or hypoplasia:
Uncommon and often associated with other anomalies. Complete absence of
cerebellar tissue is extremely rare. Hemiagenesis is less rare and is usually
associated with an atrophy of the inferior cerebellar peduncle and contralateral
inferior olive. It may be asymptomatic, even in adulthood. In the hypoplastic
cases, the cerebellar sulci displayed areas devoided of neuronal cells and
formed by gliotic tissue. There is also corresponding reduction in number of
neurons in the pontine nuclei. According to Norman et al., hypoplasias of the
whole cerebellum, in a sense that the whole cerebellum is grossly small and the
internal and external granule cells and Purkinje cells appear normal, are
virtually nonexistent. Pathologically, it is very difficult to separate
hypoplasia and degeneration. Most of the reported cases of hypoplasias are
proved to be degenerative.
#Chiari
Malformations: Cerebellar deformity associated with
hydrocephalus.
·
Type I:
Clinical:
Often asymptomatic but may also cause headache,
neck pain, and apneoic episodes and near-miss sudden death syndrome. Adults may
have cerebellar ataxia, neck pain, pyramidal syndrome, or dissociated sensory
loss indicative of syringomyelia.
Pathology: Conical elongations of the tonsils and neighbouring parts of the cerebellar hemispheres extend
into the vertebral canal (i.e., below the foramen of magnum). The protruded
cerebellar tissue could be histologically normal, infracted or sclerosed. The
medulla is either unaffected or flattened by the cerebellar tongues. Often
associated with syringomyelia (50%), hydromyelia and syringomyelia, (50%) and
hydrocephalus (10%). Chiari malformations have four subgroups:
·
Subgroup I: present
in childhood with hydrocephalus.
·
Subgroup II:
associated with anomalies including occipitalization of the atlas, Klippel-Feil
anomalies, other abnormalies of C1 and C2, and sometimes large tonsils.
·
Subgroup III:
acquired deformities of the foramen magnum such as basilar impression, often
have associated syringomyelia.
·
Subgroup IV:
tonsilla ectopia, myelomeningoceles, and other abnormalities as fenestration of
the falx and dysgenesis of the corpus callosum.
·
Type II:
Displacement of the cerebellar vermis
combined with deformities of the medulla and tectal plate. Often associated with
syringomyelia, hydromyelia, spinal bifida, meningocele, and hydrocephalus. It
can also associate with other malformation of the brain, cranium and meninges,
cardiovascular, gastrointestinal and genitourinary systems. Chiari type II
malformation is probably secondary to a neural tube defect. All Chiar II
malformations initially described has neural tube defects and the term “Chiari
II” malformation should be limited to those cases with neural tube defects.
·
Arnold-Chiari Syndrome:
Chiari type II malformation associated with meningocele.
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Type III:
Encephalocele formed by herniation of the structures of the posterior fossa,
including the cerebellum, through an occipitocervical or high cervical bony
defect. There may also be beaking of of the tectum, elongation and kinging of
the brain astem and lumbar spina bifida.
·
Type IV:
Hypoplastic cerebellum. (This term is not used anymore).
#Choristoma: Non-neoplastic, tumor-like masses of
histologically normal tissue in an abnormal location. In contrast to hamartoma,
choristomatous tissue has normal or near normal histologic architecture.
#Clinodactyly: Permanent deflection of one or more finger.
#Cerebro-ocular dysplasia and
muscular dystrophy (COD-MD): Agyric
disorder combined with malformation of the visual system. This is considered a
synonym or an entity similar to Walker-Warburg syndrome.
#Congenital: congenital malformations and structural
abnormalities refer to growth disorders with structural defects that are present
at birth.
#Coloboma: An apparent absence or defect of some ocular
tissue, usually due to failure of a part of the fetal tissue to close; it may
affect the choroid, ciliary body, eyelids, iris, lens, optic nerve, or retina.
#Colpocephaly: Refers to the disproportionate enlargement of the
occipital horns; the anterior horns of the lateral ventricles are also usually
enlarged in cerebral malformations. Because the primary fault is failure of
growth of the cerebral mantle and because the term "colpocephaly" has
been used for a heterogenous group of cases, it should not be used.
#Cortical dysplasia: Cortical dysplasia is characterized by the
presence of abnormal neurons and glia arranged abnormally in focal areas of the
cerebral cortex. The separation between cortical dyplasia and microscopic
migration disorder is arbitary, if it exists.
#Cortical lamination: Variations of abnormal cortical lamination, often
associated with polymicrogyria and pachygyria are as follows:
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Unlayered
cortex: There is a molecular layer and a single band of unlayered neurons.
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Four
layered cortex: There is a molecular layer, then a layer of unlaminated neurons
arranged in a sinus band like the tracing of a sound wave, then a straight
horizontal cell-poor layer, which in older individuals usualy contains myelin,
beneath which there is another straight hroizontal layer of unlaminated neurons.
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Parallel
four-layered cortex: This has the same four layers as the previously decribed
cortex with all layers paralleling each other.
·
Miniature
gyri: Miniature gyri are fused so that the molecular layer of adjacent gyri abut
each other, with the line of fusion being marked by prominent vessels.
·
Poorly
laminated: Four layers may not always be evident.
#Cranioarachischisis: (-rachis, Greek, the backbone or the spine) Brain
and spinal cord are exposed to the surrounding amniotic fluid, resulting in
necrosis, degeneration or angioma-like formations. The optic system, however, is
relatively well developed. Since
the neural tube has multiple simultaneous fusion sites, this phenomenon may be
explained by normal fusion of the rostral portion of the neural tube leading to
a normal prosencephalon but non-fusion of the caudal part of the neural tube.
#Cranioectomesodermal
hypoplasia: The cerebral hemispheres are covered by a thin
membrane consisted of a single layer of cuboidal epithelium overlying a thin
collagenous layer, which in turn overlay another cuboidal epithelium that
covered the cerebral hemispheres. The skull base, orbits, and facial bones were
normal. In contrast to anencephaly, there is no clavarial bone. The clivus
represents the most dorsal and cephalad bony structure.
#Cyclopia: A developmental anomaly characterized by a single
orbital fossa, with the globe absent or rudimentary, apparently normal, or
dulplicated, or the nose absent or present as a tubular appendix located above
the orbit.
#Cerebro-ocular dysplasia: A family of syndromes characterized by cerebral
cortical dysplasia and ocular abnormalities. Muscular disorder is also common.
They are better known as cerebro-ocular-muscular disease.
#Cerebro-ocular-muscular
Syndrome (COD-MD): Similar
to Warburg-Walker syndrome with the addition rising creatine phosphokinase and
electromyographic evidence of myopathy.
#Caudal Regression Syndrome
(sacral agenesis): The
caudal regression syndrome is a variable defect of lumbar vertebrae, sacrum, and
coccyx. This is a severe developmental field defect of the posterior axis caudal
blastema. The severest form is sirenomelia (mermaid syndrome). It is frequently
associated with abnormalities of the anorectal and urogenital systems and lower
limbs. The entire urinary tract can be absent. The pathogenesis is probably
related to the failure of growth of the caudal eminence. The strongest
association of caudal regression is with maternal diabetes, it has also been
related to deletion of chromosome 7q, autosomal dominant and, probably,
autosomal recessive transmission. Timing: it occurs in the primitive
streak stage during week 3 of gestation before development of the allantois, and
the allantoic vessels are usually absent. There is a single umbilical artery
that arises directly from the aorta.
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Type I: total
or partial sacral agenesis and is characterized by unilateral sacral agenesis.
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Type II:
partial agenesis of the sacrum, a normal or hypoplastic first sacral vertebra,
and a stable sacroiliac joint. This is the most frequent type.
·
Type III:
total sacral agenesis and variable lumbar agenesis, and the ilia articulate with
the lowest vertebra present.
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Type IV:
total sacral agenesis and variable lumbar agenesis, and the caudal end-plate of
the lowest vertebra rests above either the fused iliac wings or there is an
iliac amphiarthrosis.
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Currarino triad:
the combination of sacral agenesis with a presacral mass, which can include a
teratoma or anterior sacral meningocele, and anorectal stenosis. Development of
teratoma can be explained by the multipotential cells of the tail bud.
#Contiguous gene syndromes: it refers to a group of disorders characterized by
subtle cytogenetif deletions detectable by high-resolution chromosome analysis.
The recognizable phenotypes of these syndromes most likely result from deletion
of several functionally unrelated genes that are physically contiguous on a
chromosome. Clinical variation within these syndromes may be related to
different sizes of the deletions.
#Coffin-Siris syndrome: This is an ectomesodermal syndrome. Dandy-Walker
hindbrain, hypertrichosis, hypotonia, lax joints, abnormal facies, and
developmental delay,
NeuroLearn NeuroHelp Malformations General Syndromes For Comment: KarMing-Fung@ouhsc.edu