Embryologic Correlations


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OBJECTIVE:

Apply your knowledge of embryology to interpret the clinical history and pathologic findings to understand how congenital anomalies are produced.


CASE 1

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Clinical History:

A 24-year-old primigravida is now in the 18th week of her pregnancy and has felt minimal fetal movement. An ultrasound shows a markedly decreased amniotic fluid volume, and the male fetus is, therefore, poorly visualized. The fetal kidneys appear enlarged and cystic, though one kidney appears larger than the other, and the renal pelves are not enlarged. The bladder appears quite small. The pregnancy continues until 34 weeks, when a preterm delivery results from preterm labor. The baby survives less than 5 minutes.

Representative images for this patient:

Image 1.1

Image 1.2

Image 1.3

Questions:

  1. What is the embryologic abnormality?

  2. What is a karyotype likely to show?

  3. How do you explain the decreased amniotic fluid? What is this called?

  4. What other cystic disease of the kidneys can be congenital?

  5. What is the recurrence risk in this case?

  6. Name the most common urinary tract anomaly




CASE 2

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Clinical History:

A 22-year-old primigravida has had an uneventful pregnancy into the 2nd trimester, except for occasional hyperemesis gravidarum. When she sees her physician, an office ultrasound is performed. Fetal size appears to be equivalent to 18 weeks gestation. The head and extremities appear normal. There is a four chamber heart. There appears to be an open spina bifida defect that is in the mid-thoracic region. The amniotic fluid index (AFI) is normal. The fetus is female.

Representative images for this patient:

Image 2.1

Image 2.2

Image 2.3

Questions:

  1. What is hyperemesis?

  2. What embryologic problem is seen on US?

  3. What laboratory test(s) on maternal blood or amniotic fluid could be abnormal?

  4. Name conditions seen with this category of embryologic abnormality.

  5. What could be done to reduce the incidence of this condition?

  6. What are potential outcomes?

  7. What are options for the parents?

  8. Is there a maternal risk?

  9. What are options for the parents?




CASE 3

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Clinical History:

A neonate born at term to a 19-year-old woman is noted not to be gaining weight as expected. At a one month checkup, the nurse practitioner palpates fullness to the baby's abdomen. An abdominal CT scan shows a left retroperitoneal mass that is 6 cm is size and solid. The mass displaces the left kidney downward.

Representative images for this patient:

Image 3.1

Image 3.2

Image 3.3

Questions:

  1. What is the mass?

  2. What is the origin of the cells that gave rise to the mass?

  3. How does this mass occur?

  4. Name some other examples of congenital or early childhood masses.




CASE 4

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Clinical History:

A neonate is born at 38 weeks gestation after a normal, uncomplicated vaginal delivery to a 28-year-old primigravida. The prenatal course had been normal except for an elevated IgM titer to cytomegalovirus (CMV). A screening fetal ultrasound at 18 weeks showed no abnormal findings. Following birth the infant is noted to become progressively jaundiced. At 2 weeks, the neonatal serum bilirubin is 15 mg/dL. A CBC shows a Hgb of 14 g/dL, Hct 42%, and MCV 96 fL. A direct and indirect antiglobulin test are both negative. The mother's blood type is O+. A liver biopsy of the neonate shows marked cholestasis but no inflammation.

Representative images for this patient:

Image 4.1

Image 4.2

Questions:

  1. What is the probable cause for these findings?

  2. What is the embryologic abnormality?

  3. Can this be fixed?

  4. Is there a chromosomal abnormality?

  5. What is the recurrence risk?

  6. What is the significance of the CMV serologic test finding?

  7. Name some other causes for neonatal jaundice.




CASE 5

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Clinical History:

A 21-year-old man has had abdominal pain for several weeks. A CBC shows WBC count 8810/microliter, Hgb 9.9 g/dL, Hct 28%, MCV 72 fL, and platelet count 272,000/microliter. A colonoscopy is performed after a stool specimen is positive for occult blood. No lesions are seen on colonoscopy. An upper GI endoscopy is likewise unremarkable. A radiographic small bowel series shows a 3 cm outpouching in the ileum.

Representative images for this patient:

Image 5.1

Image 5.2

Questions:

  1. What is the name for this lesion?

  2. What is the embryologic origin?

  3. Why was there blood loss in this case?

  4. How common is this condition?




CASE 6

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Clinical History:

A 31-year-old G4 P2 Ab1 woman has a serum triple screen at 19 weeks gestation. The alpha fetoprotein (AFP) is 6 multiples of the median (MoM), with low human chorionic gonadotropin (HGG) and normal unconjugated estriol (uE3). An ultrasound reveals an anterior abdominal wall defect with herniation of the abdominal contents. The right hand is not visualized. There is a large deep asymmetric left cleft lip and palate without a well-defined nose. The pregnancy is terminated.

Examination of the male fetus in surgical pathology shows a large abdominal wall open defect. There is severe scoliosis. A fibrous band extends from the right edge of this defect to the right arm, constricting the forearm, with absence of the right hand. A fibrous band extends from the upper edge of the abdominal defect across the head, cutting a deep cleft through the mouth and nose. A tortuous 3 vessel umbilical cord extends from the right edge of the abdominal wall defect to the placenta and is only 10 cm long.

Representative images for this patient:

Image 6.1

Image 6.2

Image 6.3

Questions:

  1. What problem in embryogenesis lead to these findings?

  2. Name the abdominal wall defect.

  3. What is scoliosis?

  4. What would a karyotype show?

  5. What is the name for this abnormality?

  6. In some cases, a skull defect is present, but cerebral tissue is seen. What is the name for this?

  7. What chromosomal abnormalities will lead to abnormalities in the triple screen?




CASE 7

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Clinical History:

A 38-year-old G2 P1 woman had a normal term infant last year. She has an ultrasound at 17 weeks in her current pregnancy. The fetal size equivalent is 15.3 weeks. The fetal brain appears abnormal, with only a single ventricle and fused thalami. Orbits are not seen. There is a midline cleft lip and palate. An extra digit is seen on each hand and foot. Amniocentesis is performed.

The fetus is stillborn at 21 weeks. Examination of the fetus shows cyclopia with a proboscis. Postaxial polydactyly is seen on all extremities.

Representative images for this patient:

Image 7.1

Image 7.2

Image 7.3

Image 7.4

Image 7.5

Questions:

  1. What is the name for the CNS abnormalities?

  2. Describe the embryology of the CNS abnormalities.

  3. How does a cleft lip and palate occur?

  4. What is the karyotype likely to be?

  5. What is the prognosis with this type of condition?




CASE 8

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Clinical History:

A 19-year-old woman is G3 P2 and in the 19th week of pregnancy by dates. A serum triple screen shows a low unconjugated estriol (uE3) with high HCG and low AFP. The fetal size equivalent is 17.5 weeks. The head is normal in size, but there is increased nuchal thickness. The extremities appear normal. The heart has what appears to be an endocardial cushion defect with flow of blood between all of the heart chambers. The amniotic fluid index (AFI) is increased. In the abdomen is a "double bubble" sign.

Representative images for this patient:

Image 8.1

Image 8.2

Questions:

  1. What embryologic problem is seen in the thorax?

  2. What is the condition called with a high AFI and how is it most likely produced in this case?

  3. Is a chromosomal abnormality likely to be present?

  4. What would a "FISH" analysis show?

  5. What are possible outcomes?

  6. What is the recurrence risk?




CASE 9

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Clinical History:

A 22-year-old G2 P1 woman gives birth to a 3100 gm male at 38 weeks gestation. An ultrasound performed at 18 weeks showed an increased amniotic fluid index (polyhydramnios). Follow up ultrasounds revealed an increasing AFI. A stomach bubble was never visualized. Apgar scores are 6 at 1 minute and 8 at 5 minutes. The baby appears normal externally. After birth, it is noted that the baby regurgitates all feedings.

Representative image for this patient:

Image 9.1

Questions:

  1. What is the probable anomaly?

  2. What is the embryologic problem?

  3. Explain the high AFI.

  4. What is the karyotype likely to be?

  5. Name a condition in which the problem seen in this case can occur with other anomalies.

  6. Can this situation be treated?




CASE 10

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Clinical History:

A 3000 gm male is born at 40 weeks gestation via an uncomplicated vaginal delivery to a 31-year-old G3 P2 woman whose pregnancy was without any problems. Her prior pregnancies resulted in term births, and both children, now ages 2 and 5, are healthy. A physical examination of the newborn reveals no apparent anomalies. Over the next two weeks it is noted that the baby is passing minimal meconium and minimal stool. The baby's abdomen appears distended. The baby is irritable and feeding poorly and not gaining weight normally.

Representative image for this patient:

Image 10.1

Questions:

  1. What are possible embryologic abnormalities?

  2. Is there a chromosomal abnormality?

  3. What can be done for this condition?



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