Respiratory

Question 1

describe a sacrococcygeal teratoma

Answer 1

• remnants of the primitive streak may persist and give rise to a large tumor known as a sacrococcygeal teratoma
• because it is derived from pluripotent primitive streak cells, the tumor contains tissues derived from all 3 germ layers in incomplete stages of differentiation
• the most common tumors in newborn infants

Question 2

describe a hydatiform mole

Answer 2

• sometimes the embryo dies and the chorionic villi do not complete their development; that is, they do not become vascularized to form tertiary villi
• these degenerating villi may form cystic swellings called hydatiform moles, which resemble a bunch of grapes

Question 3

describe a congenital diaphragmatic hernia

Answer 3

• CDH results from defective formation or fusion of the pleuroperitoneal membrane with the other 3 parts of the diaphragm
  
  • if the pleuroperitoneal canal is still open when the intestines return to the abdomen from the umbilical cord, some intestine and other viscera may pass into the thorax, compressing the developing lungs
• CDH is the most common cause of pulmonary hypoplasia

Question 4

describe diaphragmatic eventration

Answer 4

• this results mainly from failure of the muscular tissue from the body wall to extend into the pleuroperitoneal membrane on the affected side
• in diaphragmatic eventration, part of the diaphragm has defective musculature, causing it to balloon into the thoracic cavity as an aponeurotic (membranous) sheet, forming a large diaphragmatic pouch

Question 5

describe laryngeal atresia

Answer 5

• laryngeal atresia is a rare anomaly that results in obstruction of the upper fetal airway
• distal to the atresia, the airways become dilated, the lungs are enlarged and echogenic (capable of producing echoes during ultrasound because they are filled with liquid), the diaphragm is either flattened or inverted, and fetal ascites, hydrops or both is present