Congenital cystic adenomatoid malformation of the lung is a developmental abnormality characterized by abnormal proliferation of terminal bronchioles forming cysts of varying sizes. Extensive lesions are associated with a poor prognosis due to the development of nonimmune hydrops and/or pulmonary hypoplasia. The advent of high-resolution ultrasonography has made it possible to identify these lesions during the antenatal period. With the prenatal identification of cystic adenomatoid malformations comes the potential for in utero intervention to modify the natural history of this process and prevent the development of hydrops and pulmonary hypoplasia. An instance of successful intrauterine treatment of congenital cystic adenomatoid malformation is presented.
CASE REPORTA 32-year-old primagravida was referred at 28 weeks, menstrual age, because of a cystic chest mass noted on ultrasound examination. Ultrasound evaluation revealed a 28-week fetus with a 4 cm X 3.5 cm X 2.5 cm unilocular cystic mass filling the left side of the fetal thorax, displacing the heart into the right hemithorax ( Figure 1). The fetal stomach was present in the appropriate location and the diaphragm appeared intact. No evidence of fetal hydrops was identified. Based on the ultrasound findings, congenital cystic adenomatoid malformation was felt to be the most likely diagnosis followed by pulmonary sequestration or bronchogenic cyst. Given the relative size of the cyst, the fetus was felt to be at significant risk for pulmonary hypoplasia. Likewise, with the degree of mediastinal shift present, there was concern that cardiac function could ultimately be compromised leading to nonimmune hydrops. These concerns were discussed with the parents, who strongly desired that an attempt at intrauterine therapy be made. It was therefore planned to proceed with fetal thoracentesis followed by interval placement of an indwelling shunt only if there was significant fluid reaccumulation.Cessation of fetal movement was achieved by injecting 0.3 mg of pancuronium bromide into the fetal thigh under ultrasound guidance (Acuson 128). An 18-gauge Tuohy needle was then guided into the center of the cyst. Immediately on removing the stylet, there was brisk flow of clear viscous fluid. After removal of '22 mL of fluid, the cyst had completely disappeared and heart shifted back to the left. An umbilical vein blood sample for cytogenetic analysis was then obtained from the placental insertion of the cord. Fetal heart activity remained stable throughout the procedures.Analysis of the fluid included a cell count and differential with 545 red blood cells and 355 white blood cellskmm with the differential showing 13% segs, 36% lymphs, and 51% histiocytes. Protein was less than 1.0 g/dL. Cytologic examination of the fluid revealed numerous histiocytes, karyorrhectic debris, and ciliated columnar epithelial cells. Cytogenetic analysis of the fetal blood sample yielded a normal 46,XY karyotype.Serial follow-up ultrasound scans were obtained. On the first day following the pr...