Unexpected Floyd’s type I tracheal agenesis and pulmonary hypoplasia with prenatal polyhydramnios, clinical examination methods for prenatal diagnosis of congenital trachea agenesis : a case report

<p> Tracheal agenesis（TA）is one of the congenital high air way obstruction syndrome（CHAOS）. It is rare congenital anomaly which the prevalence is less than 1:50, 000, and male to female ratio is 2:1. This disorder is characterized by complete or almost complete failure of trachea development and usually can be suspected in the presence of a CHAOS at birth. Since TA often accompanies tracheoesophageal fistula（TEF）, and in 93% of the cases of TA associates with congenital malformations, it has a few unique symptoms at prenatal ultrasound findings. Almost cases face a difficult management at birth abruptly, and few long-term survival cases have been reported ever. TA does not seem to be relate to chromosomal aberration or genetic anomaly and inheritance, embryological abnormalities are most considered. We present a case of Floyd’s type I tracheal agenesis. The patient was a 36-year-old woman, her amount of amniotic fluid volume got increasing from 26 gestational weeks, and no other malformations were not detected except congenital esophageal atresia（no gastric bubble）. Premature rapture of membrane occurred at 28 weeks’ gestation, and then C-section was performed at 33 weeks because of onset of labor and fetal pelvic presentation. Unfortunately the infant passed away at 2 hours of life, and then autopsy revealed Floyd’s type I trachea agenesis, laryngeal atresia, esophageal atresia and pulmonary hypoplasia. Fetal MRI could contribute to the prenatal diagnosis, TA have to be suspected in the presence of unexplained polyhydramnios case.</p>