Outcome of antenatally diagnosed cystic adenomatoid malformations Jeffrey A. Kuller, MD: Jerome Yankowitz, MD: James D. Goldberg, MD: Michael R. Harrison, MD: N. Scott Adzick, MD: Roy A. Filly, MD,c Peter W. Callen, MD,c and Mitchell S. Golbus, MD"

San Francisco, California OBJECTIVE: Twenty-two cases of antenatally diagnosed congenital cystic adenomatoid malformations are reported. STUDY DESIGN: Case management is reviewed. RESULTS: Eighteen women continued pregnancy after diagnosis. In nine cases nonimmune hydrops fetalis did not develop and all infants survived. Nonimmune hydrops fetalis developed in the other nine; fetal intervention was performed in eight cases. In the single case of nonimmune hydrops fetalis without intervention, the neonate died. In four cases aspiration of macrocystic leSions was performed. In two cases cystoamniotic shunts were placed. Neither aspiration or shunting provided long-term benefit. In six cases fetal lobectomy was ultimately performed and four survived. Two fetuses did not undergo in utero surgery; one was delivered prematurely after cyst aspiration and lived, and the other previable fetus was delivered soon after shunting. CONCLUSIONS: Fetal survival is best related to development of nonimmune hydrops fetalis. Aspiration of cystic lesions and cystoamniotic shunts generally provide short-term benefit. Early experience with fetal surgery for congenital cystic adenomatoid malformations has been encouraging. (AM J OSSTET GVNECOL 1992;167:1038-41.)

Key words: Cystic adenomatoid malformation, fetal lung mass, prenatal diagnosis

Congenital cystic adenomatoid malformation is a pulmonary anomaly characterized by overgrowth of terminal bronchioles. The clinical presentation may be widely variable, ranging from intrauterine fetal death secondary to nonimmune hydrops fetalis to discovery in childhood after recurrent pulmonary infections. Congenital cystic adenomatoid malformations result from failure of the endodermal bronchiolar epithelium to induce surrounding mesenchyme to form bronchopulmonary segments. If several bronchiolar divisions are involved, mediastinal shift and pulmonary, esophageal, and vena caval compression may result in polyhydramnios and fetal hydrops. 1 Congenital cystic adenomatoid malformations are almost always unilateral with no predilection to the right or left lung; the hamartomatous lesion is usually limited to one lobe. Generally, the lesion is not associated with other structural anomalies, but on occasion a variety of Fmm the Fetal Treatment Program, Department of Obstetrics, Gynecology and Reproductive Sciences, a the Department of Surgery,' and the Department of Radiology,' the University of California, San FranCISCO.

Presented at the Twelfth Annual Meeting of the Society of Perinatal Obstetricians, Orlando, Florida, February 3-8, 1992. Reprint requests: Mitchell S. Golbus, MD, Reproductive Genetics Unit, U-262, University of California Medical Center, San Francisco, CA 94143-0720. 6/6/39667

abnormalities have been reported. These include bilateral renal agenesis, renal dysplasia, hydrocephalus, cardiac defects, and diaphragmatic hernia. Isolated lesions are not generally associated with an abnormal karyotype. Congenital cystic adenomatoid malformations may be classified into three subtypes according to the size of the cysts; type I has large cysts, type II has multiple small cysts < 1.2 em in diameter, and type III consists of noncystic lesions! Adzick et al. 3 have simplified this classification into two groups; macrocystic tumors with cysts 2:5 mm in diameter and microcystic lesions with cysts