Prenatal Management of Congenital Cystic Adenomatoid Malformation of the Lung By Y. Dumez, L. Mandelbrot, N. Radunovic, Y. R6villon, M. Dommergues, M.C. Aubry, J.P. Aubry, F. Narcy, and P. Sonigo Paris, France 9 In utero evolution and postnatal outcome were studied for 18 cases of congenital adenomatoid malformation (CAM) diagnosed by prenatal ultrasound. Five were macrocystic CAM, 9 were microcystic, and 4 were homogeneously hypere- chogenic. Three fetuses presented with hydrops. Pulmonary amniotic shunting was performed in 3 patients. Outcome was the following: 4 were aborted, 1 died neonatally, and 13 survived. Four of these infants required no surgery in the neonatal or postneonatal period. In three of these, the size of the mass had decreased spontaneously in utero. Outcome did not appear to be related to the anatomic type of CAM nor to the presence of moderate polyhydramnios, but was re- lated to the degree of mediastinal compression and to the existence of hydrops. A clearer understanding of the natural evolution of CAM is useful to determine the indications for in utero therapy. Copyright 91993 by W.B. Saunders Company INDEX WORDS: Congenital cystic adenomatoid formation. T WO DISTINCT clinical presentations of congen- ital cystic adenomatoid malformation of the lung (CAM)--acute neonatal respiratory distress and later-onset recurrent pulmonary infectiont,2~have been known to pediatricians for decades. More se- vere forms have also been described, which can be fatal before postnatal management can be effective) Although ultrasound allows for prenatal diagnosis and follow-up, the natural history of CAM remains unclear. Some forms have been found to regress spontaneously during intrauterine life,4,5whereas oth- ers evolve toward pulmonary hypoplasia or hydrops.6 Recently, prenatal therapy has been performed, ei- ther by thoracocentesis,3 by pulmonary-amniotic shunting,7,8 or by fetal surgery,9 with varying degrees of success. The purpose of this study was to clarify the prognostic elements for these malformations and to better understand the indications for in utero treat- ment. From the Port Royal Fetal Medicine Unit and Fetopathology Department, Cochin Hospital, and the Departments of Radiology and Pediatric Surgery, Necker Hospital, Paris, France. Date accepted: September 25, 1991. Address reprint requests to Professor Y Dumez, Port Royal Fetal Medicine Unit, 123 Blvd de Port Royal, 75014 Paris, France. Copyright 9 1993 by W.B. Saunders Company 0022-3468/93/2801-0008503. 00/0 MATERIALS AND METHODS The study population included 18 consecutive patients referred to our level 3 fetal medicine center between 1986 and 1990 because of fetal lung malformations, detected at routine ultrasound and diagnosed to be CAM in our department. Abnormal images were identified at routine scans in a)l cases, between 19 and 25 weeks. A diagnosis of CAM was suggested by the level 1 sonographer in 10 cases, intrathoracic images remained uninterpreted in 4 cases, and a diagnosis of congenital diaphragmatic hernia was given in one case. The remaining 3 patients had routine scans performed at a level 3 center. At the time CAM was diagnosed, gestational age ranged from 20 weeks to 30 weeks from the last menstrual period, with most patients (15/18) presenting at less than 25 weeks. Lesions were classified on the basis of sonographic findings, according to the morphologic criteria proposed by Stocker et al 1~as follows: type I (macrocystic) involves a single, or more commonly, multiple large cysts, over 20 mm; type II (polymicrocystic) involves variable numbers of small cysts, under 15 mm; and type III is defined as a homogeneously echogenic lung mass without discern- ible individual cysts. In addition to the type of CAM, the following potential prognos- tic indicators were examined: size of the lesion, localization, amount of amniotic fluid, presence or absence of hydrops. Polyhy- dramnios was defined on a qualitative scale: moderate (+) when excess amniotic fluid was evident at ultrasound and major (+ +) when it was responsible for clinically obvious uterine distension. We evaluated the size as the percentage of the overall pulmonary area appearing pathological at ultrasound. It was considered to occupy less than 50% of the thorax when it was unilateral and ipsilateral lung tissue could be identified. When no normal lung was seen on the side containing the CAM, in the absence of mediastinal shift, it was considered as occupying 50% of the thorax. When a convex diaphragm and/or marked mediastinal shift was observed, the size was graded as more than 50% of the thoracic area. One case was bilateral with no normal pulmonary paren- chyma seen and was therefore graded as occupying 100% of the thorax (excluding mediastinum). Thirteen patients were subsequently followed in our center; the remaining 5 were followed in their original level 1 department after the diagnosis of CAM was confirmed in our center. For the patients followed in our center, fetal karyotyping was performed in all cases. Evolution was monitored by serial ultrasound examinations at 1- to 3-week intervals. CAM of the anatomical type suggested by ultrasound was confirmed by pathology in all 13 cases, for which autopsies or surgical resections were performed. In three severe cases, in utero drainage was decided to correct or avoid hydrops and pulmonary hypoplasia. Shunting was performed using double-ended pigtail catheters, according to the technique published by Nicolaides et al. 8 Before shunting, fetal neuromuscu- lar blocade was obtained by an injection of vecuronium bromide (0.1 mg/kg estimated fetal weight) into the umbilical vein. Briefly, a metal cannula was introduced into the amniotic cavity and through the fetal chest wall into the largest cyst, under ultrasound guidance. 36 Journal of Pediatric Surgery, Vo128,No 1 (January), 1993:pp 36-41