Anat Path Flashcards
Indicate the chromosomal constitution of a (complete) mole and state what conclusion can be drawn regarding its origin (2)
46XX. All the “tumour” is of paternal origin (“androgenetic”). Total paternal origin (empty ovum plus 46- 2 sperm fertilise)
Explain how the typical microscopic structure determines the macroscopic appearance of a complete mole (2)
The absence of vessels in the villi causes them to become very enlarged and hydropic (swollen) – accounting for the typical “bunch of grapes” macroscopic appearance
Microsc the villi show hydropic degeneration with marked troph prolif macroscopically you will not see any normal villi
Briefly discuss the possible links between a mole and a suspected brain metastasis (4)
- The potential for persistent trophoblastic disease (in particular, choriocarcinoma) to develop from a partial mole is small, is greater for the complete variety – but is low overall
- Choriocarcinoma typically disseminates very widely – haematogenously (first to the lungs and then from there via the systemic arterial circuit to multiple sites amongst which the brain is common) [These could, pedantically, be called “tertiaries” – unless Batson’s plexus is invoked]
- Haematogenous- mole extends through uterus and may enter blood stream
Dr Brown is called to evaluate a newborn infant in the labour ward. On physical exam he notes that the infant has normal vital signs and appearance with the following exception. Dr Brown notes that the infant has a bulging cyst-like structure approximately 4 cm in diameter protruding from his back. He also observes that the baby has limited movement of the lower extremities and that both feet are plantar flexed and inverted at the ankle.
List two (2) possible names for the bulging cyst on the back of the infant (1)
Meningocoel, meningomyelocoele - NOT myelocoele
Explain the limited movement of the lower extremities (1)
Malformation of the spinal cord causing lack of neural innervation to the limbs
Name the abnormality of the feet (½)
Clubfeet
Explain the position of the feet (1) & List five (5) other causes of your answer (2½)
Paralysis /absence of muscle activity/compression causes deformation (1)
Causes of anhydramnios e.g. bilateral renal agenesis/bilateral cystic renal dysplasia/urethral atresia; causes of fetal akinesia/absent movement e.g. cerebral pathology, other causes of spinal disease (neuronal loss); muscle weakness
The aetiology of NTD is multifactorial. List three (3) independent factors which may play a role in its aetiology and give an example of each (3)
Genetic e.g. monogenic mutations, chromosomal trisomy 18; environmental including specific geographic areas, maternal diet - folic acid deficiency, iatrogenic - drugs taken by mother (valproate), metabolic - maternal diabetes
List two (2) methods to detect NTDs antenatally (1)
Careful ultrasound examination/screening of maternal blood or amniotic fluid for raised AFP
Explain the association of a spinal NTD and bilateral club feet (2)
- Lumbosacral NTD frequently results in paralysis /weakness/akinesia of lower limbs
- Frequently associated with hydrocephalus which is often in a breech position -Arnold Chiari malformation
- Could be a syndromic association
Baby was born with a meningomyelocoele in the lumbosacral area of his spine. O/E: limbs showed no sensory or motor deficits of the upper limbs, but the lower limbs had reduced muscle reflexes, were bowed in position, and there were areas of sensory loss on the skin. Preparations are underway for surgery to the lesion on his back.
List two (2) unrelated investigations whereby a meningomyelocoele can be suspected in utero (2)
Ultrasound examination (1) and maternal serum and/or amniotic fluid alpha foetoprotein levels (1)
How can the risk of this lesion be reduced? (1)
Planned pregnancy with folate (½) for 3 months prior to conception (½)
This baby develops hydrocephalus. Explain the likely pathogenesis (4)
Hydrocephalus due to Arnold- Chiari malformation causing obstruction to CSF flow at the level of the foramen magnum due to downward displacement of the cerebellum]
Explain how a spinal neural tube defect (NTD) can cause congenital hydrocephalus (2)
Obstruction of foramen magnum by displaced cerebellum from tethered cord
State how many ventricles are dilated in this type of hydrocephalus (½)
4
State the name of this malformation (½)
Arnold Chiari malformation
List four (4) complications/effects of an untreated lumbar meningomyelocoele (2)
Paraplegia of legs/ urinary incontinence/ fecal incontinence/ ascending meningitis
Briefly describe three (3) causes of hydrocephalus in the newborn (3)
Arnold Chiari malformation with NTD/ acquired haemorrhage occluding aqueduct/acquired inflammation postmeningitis occluding aqueduct of Sylvius/ mutant genes
List four (4) features of hydrocephalus in the newborn (2)
Macrocephaly/ wide open sutures/ large fontanelles/ relatively small face
Outline two (2) common outcomes in a neonate/ newborn with hydrocephalus if untreated (2)
Progressive intellectual impairment/spastic paraplegia/cerebellar ataxia
46 y/o becomes pregnant with her 3rd child. On routine antenatal ultrasound the doctor suspects that the fetus may have a NTD. Patient is counselled on the implications of NTD’s for the child and the family and offered a termination of pregnancy which she refuses. At delivery by Caesarian section the infant is born with a large closed encepholocele.
State the most likely site of the defect (½)
Occipital region
State the prognosis of this infant. Explain your answer (2)
Poor; there will be abnormal neuronal cortical migration in this region. There is likely to be cerebellar involvement with abnormality of gait & balance.
Name the most common cause of congenital hydrocephalus (1)
Arnold Chiari malformation type II
Indicate the primary mechanism for the hydrocephalus associated with your answer in the previous question (1)
Spinal neural tube defect/ meningomyelocoele
