Congenital cystic adenomatoid malformation

Australasian Journal of Ultrasound in Medicine August 2009; 12 (3) Introduction Congenital cystic adenomatoid malformation (CCAM) is an uncommon fetal lung anomaly involving cystic changes to the terminal bronchioles. The condition requires close monitoring during the antenatal period with ultrasound in addition to input from the neonatal and paediatric surgical teams. This case study involves a 27-year-old female, G2P1, who was referred by her obstetrician to the Maternal Fetal Medicine Unit (MFM-U) with a morphology scan finding of a cystic mass in the left hemi thorax, most likely a CCAM. The report described a multicystic mass in the left chest occupying at least 50% of the left hemi-thorax. The right lung appeared normal as did the fetal heart and no other anomalies were detected at this initial scan. The morphology scan was repeated at the MFM-U at 20 weeks gestation. This scan confirmed an isolated left-sided Type 1 (macro cystic) CCAM with evidence of mediastinal shift. In addition to these findings, an isolated choroid plexus cyst (CPC) and an echogenic focus in the left cardiac ventricle were also identified. Fetal anatomy was otherwise normal. At this stage the patient was counselled about the variable prognosis of CCAM, which primarily is dependent on whether fetal hydrops (heart failure) develops. At this pre-viable gestational age, the patient was counselled that the cysts could be drained in the event of further enlargement with the aim of avoiding cardiac compromise and subsequent development of hydrops fetalis. In addition, while the findings of CPC and the echogenic intracardiac focus did increase this patient’s risk of a chromosomal problem slightly (risk trisomy 21 = 1:270), the patient was counselled that chromosomal problems are not reported in association with CCAM thus making aneuploidy unlikely in this case. The patient declined further testing. Ultrasound evidence of a large CCAM lesion and early mediastinal shift placed this pregnancy at very high risk for significant complications including non-immune hydrops. Accordingly, a clear management plan with multidisciplinary counselling was instituted early for the patient and her family including close ultrasound surveillance, at least every two weeks, for the monitoring of fetal well-being and the early detection of fetal hydrops and polyhydramnios. Counselling by the neonatology and paediatric surgical teams was organised to provide important information regarding management issues in the neonatal period. A fetal echocardiogram was performed at 24 weeks showing a structurally normal fetal heart with deviation of the fetal heart to the right side of the chest. In addition, the large leftsided complex lung cysts seen on imaging were not causing any compression of the cardiac chambers or causing any cardiac inflow obstruction. While regular ultrasound scanning of the fetus did not identify any signs of fetal hydrops, gradually enlarging fetal lung lesions, persisting right mediastinal shift and polyhydramnios complicated the pregnancy. Growth and Doppler studies remained normal. In an effort to lessen the effect of mediastinal shift on normal lung development, in-utero thoracocentesis was performed on three occasions. In addition, Congenital cystic adenomatoid malformation