Pathology and Radiology: Developmental Pathology Flashcards
Define malformation
Define dysplasia
Malformation: when an ORGAN fails to form properly
Dysplasia: when a TISSUE fails to form properly
At what days does neurulation typically occur?
Days 17-30
Open defects caused by failure of dysjunction of neural and cutaneous ectoderm is caused by a neural tube defect in what stage?
What are examples of this pathology?
Neurulation defects
Myelomeningocele, spina bifida, myelocele, anencephaly
Closed, skin-covered deficits are usually due to a neural tube problem happening at what point in neural tube development?
What are examples?
Post-neurulation (26-60 days)
Spina bifida occulta, holoprosencephaly, encephaloceles, hydrocephalus, lipoma, meningocele, Chiari malformation
What is the most common congenital malformation?
What is their ultimate prognosis?
Ancencephaly (absence of scalp and skull)
Either still born or die within 2 months
Patients with anencephaly have increases in what proteins in their amniotic fluid?
AFP and acetylcholinesterase
What is exencephaly?
Cerebral hemispheres are present but abnormal with associated defects to calvarium and skull base
What are risk factors for myelomeningocele?
Reduced vitamin A or folate intake, depakote or carbamazepine use, parental consanguinity
Nearly 100% of patients with myelomeningocele will also have what developmental abnormality?
Chiari II malformation
L5 bifid spinous process is associated with what developmental abnormality?
Spina bifida occulta
Where do occipital cephaloceles often develop?
What gender is most likely involved?
Between the foramen magnum and lamboid suture
More often involves females
Where do parietal cephaloceles often develop?
What gender is more often involved?
Between the lambda and bregma
More often in males
What is the most frequent type of cephalocele in southeast asian and australian aborigines?
Sincipital/Frontoethmoidal cephalocele
Absence or erosion of the crista galli may lead to what type of cephalocele?
Nasal/Sphenoethmoidal cephalocele
What type of cephalocele is associated with dermoid, epidermoid, and nasal gliomas?
Nasal/Sphenoethmoidal cephaloecele
What type of neural tube defects are caused by faulty segmental disjunction leading to formation of epithelium-lined tracts?
Dermal sinus tracts
What are the most frequent sites for dermal sinus tracts?
50% may end in what type of pathology?
Lumbar, followed by occipital
Dermoids and epidermoids
What are the hallmarks of Meckel-Gruber Syndrome?
What maternal event during days 20-26 of gestation is it associated with?
Dysplastic and cystic kidneys, cardiac anomalies, orofacial clefting, and cephaloceles
Associated with maternal hypothermia
Cleavage disorders are due to defects in what germ layer?
Prechordal mesoderm
What are the three types of holoprosencephaly and describe their characteristics.
Alobar: No midline structures (i.e. falx, corpus callosum, septum pellucidum), monoventricle, failed division of forebrain, fused basal ganglia and thalamus, severe craniofacial abnormalities such as cyclopia
Semilobar: Partial division with presence of partial falx and interhemispheric fissure with partial separation of basal ganglia and thalamus, variable craniofacial abnormalities are present
Lobar: No corpus callosum but additional midline structures present with squared frontal horns of ventricles and no craniofacial abnormalities
What is arrhinencephaly?
Absence of olfactory bulbs and cortex with replacement of corpus callosum by grey matter
Associated with holoprosencephaly and Kallman syndrome (anosmia, hypogonadism, mental retardation)
Describe the features of septo-optic dysplasia (aka de Morsier syndrome)
Absent septum pellucidum, schizencephaly, and hypoplastic optic nerves. Occurs in lobar holoprosencephaly.
Associated with seizures, hypotelorism, visual symptoms, and precocious puberty
Delayed closure of fontanelles, retention of mandibular teeth, wormian bones, and midline defects are all seen in what?
Cleidocranial dysostosis
During what gestational months do normal neuronal migration occur?
2nd to 5th months
Define heterotopias
Normal neurons in abnormal CNS locations (i.e. centrum semiovale, cerebellar white matter)
Typically do not enhance
Define ectopias
Neurons in locations they should not be in (i.e. subarachnoid space)