Pathology Congenital Anomalies

Question 1

Discuss Intestinal Atresia

Answer 1

Incomplete development of GIT that causes mechanical obstruction. Usually discovered after birth due to regurgitation during feeding. Incompatible with life, need surgery.

Question 2

Morphology and associations of Intestinal Atresia.

Answer 2

Segment of small bowel lacking a lumen. ‘String of sausages’ apperance.
Associations with Trisomy 21 and cystic fibrosis.

Question 3

Discuss Stenosis

Answer 3

Incomplete atresia with narrowed lumen due to thick wall.

Question 4

Discuss Imperforate Anus

Answer 4

Most common form of congenital atresia. Caused by failure of cloacal diaphragm to involute

Question 5

Discuss Meckel Diverticulum

Answer 5

Most common true type diverticulum. Caused by a persistent vitelline duct

Question 6

Meckel Diverticulum rule of 2’s

Answer 6

Within 2 ft of ileocecal valve, 2% of population, 2 inches long, Twice as common in males, Symptomatic by age 2.

Question 7

Complications of Meckel Diverticulum

Answer 7

Heterotopic gastric mucosa can be present. Acid secretion can lead to ulcers. Can mimic appendicitis.

Question 8

Discuss Ectopic Tissue

Answer 8

Usually in upper third esophagus (inlet patch)

Question 9

Pathogenesis of Hirschsprung Disease

Answer 9

Disruption of normal migration of neural crest cells from cecum to rectum. Absence of ganglion cells of colonic nerve plexus results in loss of motor function. RET gene

Question 10

Morphology of Hirschsprung Disease

Answer 10

Always affects rectum.
Aganglionic region can appear normal or contracted; nerve bundles hypertrophied with absence of ganglion cells.
Normal segments progressively dilate, wall hypetrophys then thins and may rupture.

Question 11

Diagnosis of Hirschsprung Disease

Answer 11

Biopsy with absence of ganglion cells

Question 12

Causes of Acquired Megacolon

Answer 12

Chagas Disease (also loss of ganglia), Mechanical obstruction, Visceral myopathy, infections

Question 13

Discuss Duplication

Answer 13

Can occur anywhere in GIT though most common in ileum. Communicating type may be lined with gastric mucosa.
Cystic type may cause obstruction

Question 14

Discuss Malrotation

Answer 14

Defective intestinal rotation in fetal life. Abnormal positions of small and large bowel with anomalous attachment bands. Can cause volvulus and internal hernias

Question 15

Differentiate Omphalocele from Gastroschisis

Answer 15

Omphalocele: At base of umbilical cord, covered by amnion and parietal peritoneum
Gastroschisis: No associated covering and not attached to umbilical cord. Not associated with malrotation.

Both conditions have elevated alpha-fetoprotein