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Congenital lung lesions are a rare group of developmental pulmonary abnormalities that are often first identified prenatally on routine second-trimester US. Congenital pulmonary airway malformation (CPAM) is the most common anomaly while others include bronchopulmonary sequestration, congenital lobar overinflation, bronchogenic cyst and bronchial atresia. Clinical presentation is highly variable, ranging from apparent in utero resolution to severe mass effect with resultant hydrops fetalis and fetal demise. Differentiation among these lesions can be challenging because overlapping imaging features are often present. The roles of the radiologist are to identify key imaging findings that help in diagnosing congenital lung lesions and to recognize any ominous features that might require prenatal or perinatal intervention. High-resolution US and complementary rapid-acquisition fetal MRI provide valuable information necessary for lesion characterization. Postnatal US and CT angiography are helpful for lesion evaluation and for possible surgical planning. This article reviews the embryology of the lungs, the normal prenatal imaging appearance of the thorax and its contents, and the prenatal and neonatal imaging characteristics, prognosis and management of various congenital lung lesions.

Congenital lung malformations are most often identified on prenatal US screening. Fetal MRI is often performed to further evaluate these lesions. Although some of these lesions might cause prenatal or early postnatal symptoms that require urgent management, the majority are asymptomatic at birth and might be subtle or invisible on chest radiographs. Postnatal imaging is frequently deferred until 3–6 months of age, when surgery or long-term conservative management is contemplated. High-quality imaging and interpretation is needed to assist with appropriate decision-making. Contrast-enhanced chest CT, typically with angiographic technique, has been the usual postnatal imaging choice. In this review, the author discusses and illustrates the indications and use of postnatal MR imaging for bronchopulmonary malformations as well as some differential diagnoses and the advantages and disadvantages of MR versus CT.

Fetal lung lesions include common lesions such as congenital pulmonary airway malformation (CPAM), bronchopulmonary sequestration (BPS) and combined CPAM-BPS hybrid lesions, as well as less common entities including congenital lobar emphysema/obstruction, bronchial atresia, bronchogenic cysts and rare malignant pulmonary lesions such as pleuropulmonary blastoma. Fetal lung lesions occur in approximately 1 in 15,000 live births and are thought to arise from a spectrum of abnormalities related to airway obstruction and malformation, with the lesion type depending on the timing of insult, level of bronchial tree involvement, and severity of obstruction. Lesions vary from small and asymptomatic to large and symptomatic with significant mass effect on surrounding structures. Accurate diagnosis and characterization of these anomalies is crucial for guiding patient counseling as well as perinatal and postnatal management. The goal of this review is to provide an overview of normal fetal lung appearance and imaging features of common and uncommon lesions on both ultrasound and MR imaging, and to discuss key aspects in reporting and evaluating the severity of these lesions.

Congenital pulmonary airway malformation (CPAM) is classified into pathologically different types. These types are sometimes distinguishable by fetal lung MRI and are usually observed as higher-signal lesions on T2-weighted images than normal lung. We describe a case of unusual CPAM resembling neoplasms, with a lower signal than is found in normal lung. Histopathology showed a large number of mucogenic cells but found no evidence that could explain this feature on fetal MRI. An unusual low-signal mass associated with a pulmonary cyst in fetal lung on MRI may suggest an unusual type 1 CPAM.

Background. The purpose of this study was to attempt to improve upon conventional coronal computed tomographic (CT) images of neonatal chest which to date have been made by reformatting thinly spaced axial images. Materials and methods. Nine neonates were studied by direct coronal CT scans with the patients' long axis 90 degrees to the scanning table. They were studied to further define their thoracic abnormalities detected on plain film. Spiral CT and cine scan (Imatron) were utilized. Results. Congenital lung lesions such as congenital cystic adenomatoid malformation could not be diagnosed but their anatomical location could be accurately depicted, enabling easier surgical planning. The arterial supply to bronchopulmonary sequestrations was also identifiable. Tracheobronchial abnormalities such as tracheobronchus and bronchial atresia were also identifiable. Causing of air trapping, both intrinsic such as an atretic bronchus and extrinsic such as vascular compression were readily demonstrated. Conclusion. With neither special devices nor paraphernalia, the described method of direct coronal CT scans were both feasible and provided significant information. This technique allows for improved assessment of the tracheobronchial tree and more accurate detection, localization, and characteristics of lesions adjacent to the diaphragm.

Fetal therapy is a logical extension of fetal diagnosis. Fetal surgery has been performed in humans for the past 10 years. During this time, technical obstacles have been overcome and the natural history of many fetal disorders has been defined. A select group of disorders amenable to potential improvement by fetal treatment has been identified including fetal urinary tract obstruction, fetal diaphragmatic hernia, fetal congenital cystic adenomatoid malformation and fetal sacrococcygeal teratoma. The fetal surgical experience with each of these lesions is reviewed and the maternal risk of fetal surgery is discussed.

A 23-year-old woman at 25 weeks’ gestation who had developed twin–twin transfusion syndrome (TTTS) was referred to our hospital for further evaluation. MR imaging (single-shot fast spin-echo) was performed to evaluate the state of the fetal brains. The brain of the recipient twin was normal, but both lungs were diffusely cystic (Fig. 1). The parents decided to terminate the pregnancy and the diagnosis of congenital cystic adenomatoid malformation (CCAM) was confirmed at autopsy. CCAM is characterized by adenomatoid proliferation of cysts in the lung resembling bronchioles and is of unknown pathogenesis. Increased cell proliferation, decreased apoptosis, and local disturbances of normal lung growth factors have been suggested [1]. The present case could also suggest that the imbalance of blood flow in the recipient in TTTS plays an important role in the development of CCAM. The coexistence of TTTS and CCAM, as in this case, supports the association described by Kline-Fath et al. [2].

Background: The majority of congenital cystic adenomatoid malformation (CCAM) lesions are diagnosed antenatally. A few cases however may not be recognised antenatally and present in infancy or later childhood with chest symptoms, including chest infection. Objective: To review the clinical and radiological spectrum of CCAM, comparing the antenatally with the postnatally diagnosed cases. Materials and methods: Fifteen cases of antenatally and/or postnatally diagnosed and histopathologically proven CCAM were retrospectively identified over a period of 4 years. Clinical notes, chest radiograph and chest CT were reviewed in all cases. Results: Nine patients were diagnosed antenatally and six postnatally. All antenatally diagnosed patients were asymptomatic at birth, six remained asymptomatic until they had elective surgery and the remaining three developed symptoms before the age of 2 years. In the postnatally diagnosed group, one patient was symptomatic at birth and one patient presented at 16 years; the remaining four presented before the age of 2 years. Depending on the type of lesion, we recognised five radiographic patterns of CCAM. CCAM lesions were classified as CT Stocker type I in seven cases, type II in seven cases and type III in one case. Conclusions: No significant difference was found between the two groups. Recognition of these lesions antenatally would benefit patients by avoiding delay in making the diagnosis, which can lead to serious complications. CT was successful in accurately diagnosing and grading CCAM lesions.

The differential diagnosis of echogenic areas in the fetal chest include congenital diaphragmatic hernia (CDH), cystic adenomatoid malformation (CAM), sequestrated lung and tracheal or bronchial atresia. The purpose of this study was to evaluate the accuracy of prenatal diagnosis and document outcome in fetuses with echogenic chest lesions. Seventeen fetuses with echogenic chest masses were seen in our unit between 17 and 36 weeks' gestation over a 5-year period. We reviewed these cases retrospectively for prenatal diagnosis, postnatal diagnosis and outcome. Prenatal diagnosis was correct in 13 fetuses, with CDH in 8, sequestrated lung in 4 and tracheal atresia in 1. Four fetuses had incorrect or uncertain prenatal diagnoses. In three fetuses CDH and CAM could not be differentiated. After delivery two of these had CDH and one had sequestrated lung. One fetus with bilateral lesions had prenatal diagnosis of bilateral CAM. Post-mortem examination revealed tracheal atresia as part of Fraser syndrome. All five babies with sequestrated lung are well and none required surgery. Ten fetuses had CDH, two pregnancies were terminated, one died in utero, five died as neonates and two babies survived following surgery. The study reveals that in a minority of fetuses CDH and CAM could not be differentiated prenatally. We agree with recent reports of fetal sequestrated lung describing sonographic improvement in utero. A large lesion on initial scan does not necessarily predict a poor neonatal outcome in this condition. This, together with the poor outcome in fetuses with echogenic CDH and tracheal atresia, has important implications for prenatal counselling.

Many associations of congenital anomalies of the respiratory system have been reported, but the combination of tracheal diverticulum and cystic adenomatoid malformation (CCAM) is unique. We present a patient with these two anomalies and analyze their embryological correlation.

Background. The “disappearance” of congenital masses of the lung on prenatal sonograms has been described, but the importance of postnatal imaging studies in these children is unknown. Objective. The objective of this work was to study the utility of radiographs and CT scans in asymptomatic infants with congenital masses of the lung that partially or completely resolve on prenatal sonograms performed late in gestation. Materials and methods. The prenatal sonograms, postnatal imaging studies, surgical findings, and pathologic diagnoses of seven children with an echogenic mass of the lung that improved or disappeared on prenatal sonograms were reviewed. Results. All masses were type II congenital cystic adenomatoid malformation, with features of intralobar sequestration also being found in four. An unsuspected extralobar sequestration adjacent to a left lower lobe mass was found at surgery in one patient. All masses were hyperechoic compared with normal lung on sonograms prior to 32 weeks of gestation, with cysts being seen in four. On scans after 32 weeks, four of the masses had resolved completely and three showed subtle increased echogenicity compared with normal lung. Cysts completely resolved in two of four cases. Postnatal radiographs showed subtle abnormalities in four infants, a hyperlucent lobe in one, a soft tissue mass with adjacent hyperlucency in one, and normal findings in one. CT scans were abnormal in all cases, with air-filled cysts and soft tissue in six and a hyperinflated lobe in one. Conclusion. Children with “disappearing” fetal lung masses have persistent abnormalities after birth that are often subtle on radiographs but are well demonstrated with CT.

We report a rare case of cystic intrapulmonary lymphangioma involving the left lung, which presented with pneumothorax and respiratory distress in a 6-month-old infant. Chest radiographs showed a multicystic lesion in the left lung mimicking the features of congenital cystic adenomatoid malformation of the lung. The lesion appeared on high-resolution CT (HRCT) as a multiseptate, air-filled cystic lesion in the left hilar area. Associated HRCT findings were thickening of interlobular septa and bronchovascular bundles in the left lung and the presence of peripheral pulmonary vessels within cystic lesions in the apex of the left lung. HRCT findings correlated well with histopathologic findings. We suggest that these associated findings may be helpful in distinguishing this condition from other cystic lung diseases and that this entity should be included in the differential diagnosis of multicystic lung lesions.

A cystic fetal chest mass showing spontaneous improvement in utero is described. This mass was shown to be an extralobar pulmonary sequestration with associated cystic adenomatoid malformation type 2.

A neonate presented for an esophageal atresia repair and developed respiratory distress in the immediate post-operative period. The initial conventional chest radiographs suggested that there was a right sided pneumothorax; however, this did not resolve, even after the placement of two chest tubes. A CT examination suggested that the findings were due to hyper-inflation of the right upper lobe. Thoracoscopy was performed and revealed a complex pneumothorax composed of bubbly mucous from a post-operative pleuro-esophageal fistula.

Congenital cystic adenomatoid malformation of the lung (CCAM) is an uncommon developmental abnormality presenting most often in the neonatal period. We report the clinical, radiological and pathological findings in a 9-year-old boy who presented with acute chest pain.