Congenital cystic adenomatoid malformation of the lung coexisting with recombinant chromosome 18. A case report.

Objective: Diagnosis of congenital cystic adenomatoid malformation of the lung (CCAM) in association with recombinant chromosome 18. Method: Ultrasound diagnosis of a CCAM and hydrops was made. The mother was known to have a pericentric inversion of chromosome 18 and had a previous pregnancy with a recombinant chromosome 18 (partial deletion of 18p and partial duplication of 18q). Cordocentesis for karyotype was therefore performed. Result: Fetal karyotype revealed a recombinant chromosome 18, this time with partial deletion of 18q and partial duplication of 18p. Postmortem confirmed a type III CCAM and a septum primum atrial defect. Conclusions: Although deletion/duplication of chromosome 18 is commonly associated with a wide variety of anomalies, the association with CCAM is an unusual one. Fetal and parental karyotyping should be considered in cases of CCAM, because fetal therapy is increasingly being considered in these pregnancies. Current management of parents with pericentric inversions must rely on invasive diagnostic testing in the second trimester because predicting the likelihood of an unbalanced karyotype and phenotype in a fetus is difficult.