Disappearing lung echogenicity in fetal bronchopulmonary malformations: a reassuring sign?

A Series of Congenital High Airway Obstruction Syndrome - Classic Imaging Findings

Congenital high airway obstruction syndrome (CHAOS) is a very rare entity with very poor prognosis in which upper airway is intrinsically obstructed, the most common reason being laryngeal atresia. In summary prenatal early diagnosis of patients with CHAOS is necessary so that perinatal management can be undertaken successfully or elective termination of pregnancy can be undertaken. The fetoscopic approach may be a life saving modality in a subset of CHAOS patients. Involving a multidisciplinary team comprising of paediatricians, radiologists, obstetricians and anaesthesiologists increases the efficiency of management.

Fetal cystic lung lesions: evaluation with magnetic resonance imaging

OBJECTIVES

To investigate the contribution of magnetic resonance imaging (MRI) to the diagnosis of fetal cystic lung lesions found on routine prenatal ultrasound (US).

STUDY DESIGN

Experienced radiologists retrospectively reviewed 34 fetal MRI studies performed in 20 fetuses (from 20 to 35 gestational weeks; including 14 repeat studies 10 weeks after the initial MRI), focusing on shape, signal characteristics, feeding artery, volume change, and location of the cystic lesions. Diagnoses were confirmed after birth by postnatal multidetector computed tomography (MDCT) and/or surgery.

RESULTS

Bronchopulmonary sequestration (BPS) in the second trimester appeared as a well-defined, homogeneous, hyperintense mass (pure BPS) in eight cases or as a lobulated, inhomogeneous hyperintense mass (BPS mixed with congenital cystic adenomatoid malformation (CCAM)) in three cases. The feeding artery was visible in all 11 cases in the initial MRI, and regression of the mass was seen in 7 cases. As the mass regressed in the third trimester, the signal intensity decreased, becoming inhomogeneous, and the margins became lobulated. The mean initial ratio of the volume of the BPS lesion to the ipsilateral lung in lesions with partial regression was 82%; the mean initial ratio in lesions with nearly complete regression was 61%. CCAM (6) cases also appeared as a hyperintense lobulated mass, and as the lesions regressed, they decreased in size and signal intensity. As with BPS, the larger the lesion on initial MRI, the less likely it was to regress completely. Congenital lobar fluid overload in three cases appeared as a hyperintense, homogeneous lobe with stretched hilar vessels.

CONCLUSION

Prenatal MRI is useful as a diagnostic tool complementary to US for evaluating fetal cystic lung lesions. Smaller lung lesions (<60%) may regress completely.

Prenatal diagnosis and outcome of echogenic fetal lung lesions

OBJECTIVE

To describe the antenatal findings and outcome of fetuses with echogenic lung lesions.

METHODS

This was a retrospective study of the prenatal sonographic features, antenatal management and outcome of 193 fetuses with an echogenic lung lesion diagnosed at 18-35 weeks of gestation. There were nine cases of congenital high airway obstruction syndrome (CHAOS), 170 cases of cystic adenomatoid malformation (CAM) and 14 cases of pulmonary sequestration (PS). A literature search was also carried out to compare our data with those of previous series.

RESULTS

The prognosis in our series of fetuses with CHAOS was invariably poor, but the literature describes a handful of survivors after delivery by Cesarean section and ex-utero intrapartum therapy (EXIT). Of the cases in our series with PS and no pleural effusions, more than 95% survived; in half of these cases the lesion resolved antenatally and in the other half sequestrectomy was carried out postnatally. In cases with PS and pleural effusions, successful treatment was provided by the placement of thoracoamniotic shunts or occlusion of the feeding blood vessel by ultrasound-guided laser coagulation or injection of sclerosants. In cases with CAM and no hydrops, there was more than 95% survival and in up to half of the cases there was sonographic evidence of spontaneous antenatal resolution of the hyperechogenic lesion, which was confirmed by postnatal imaging in about 60% of the cases. Of the cases with CAM with hydrops managed expectantly, more than 95% died before or after birth. Of the cases with macrocystic CAM with hydrops, two-thirds survived after placement of a thoracoamniotic shunt. In cases with microcystic CAM with hydrops, there is some evidence that open fetal surgery with lobectomy could improve survival but such treatment is highly invasive for the mother.

CONCLUSIONS

CHAOS is a severe abnormality, whereas CAM and PS are associated with a good prognosis. In a high proportion of fetuses with hyperechogenic lung lesion, there is spontaneous antenatal resolution and the underlying pathology may be transient bronchial obstruction.

More or less CHAOS: case report and literature review suggesting the existence of a distinct subtype of congenital high airway obstruction syndrome

Congenital obstruction of the upper airway (CHAOS) is a rare, usually lethal abnormality. A literature review of 36 prenatally diagnosed cases of CHAOS and the analysis of our own case suggest the existence of a distinct subtype of CHAOS, raising important implications for diagnosis and management. Serial fetal ultrasound examinations at 17-23 weeks' gestation showed hyperechoic and enlarged lungs, mediastinal shift, flattened diaphragm, polyhydramnios and apparently fluid-filled esophagus, findings interpreted as bilateral cystic adenomatoid malformation Type III. Ultrasound findings normalized around 32 weeks. The diagnosis of CHAOS was made after birth at term by direct laryngoscopy prompted by ventilatory difficulties and failed attempts at intubation. A pinhole opening posterior to the cricoid cartilage allowed the passage of an endotracheal tube. Based on observations in our case and those of five similar cases in the literature, we describe for the first time a subtype of CHAOS that is characterized by minor pharyngotracheal or laryngotracheal communications and associated with a less severe natural history and even resolution of ultrasound findings. In spite of this, a high index of awareness should be maintained because resolution of ultrasound findings does not necessarily indicate resolution of underlying pathology.

Large fetal congenital cystic adenomatoid malformations: growth trends and patient survival

PURPOSE

The prognosis for fetuses with large congenital cystic adenomatoid malformations (CCAMs) remains uncertain. This study examined the natural history of large fetal CCAMs managed expectantly at a major referral center.

METHODS

A 5-year retrospective review was conducted on fetuses diagnosed with a thoracic lesion (n = 59). Large CCAMs were identified on prenatal imaging and followed longitudinally. Perinatal outcomes were assessed.

RESULTS

Twelve (20.3%) fetuses had large CCAMs in the absence of other congenital anomalies. Peak CCAM size occurred at 25.3 +/- 3.6 weeks' gestation. Serial magnetic resonance volumetry demonstrated a trend toward decreasing CCAM mass volume relative to thoracic cavity volume over time. Overall, 6 patients, including 3 with signs of early hydrops, showed a marked regression of their lesions relative to estimated fetal weight. Five fetuses required an emergent intervention postnatally, including extracorporeal membrane oxygenation support (n = 1), cyst aspiration (n = 1), and lung resection (n = 5). Overall survival was 75%, with severe hydrops before 30 weeks seen in all 3 deaths.

CONCLUSION

Large fetal CCAMs tend to peak in size at 25 weeks' gestation and are characterized by in utero diminution relative to overall fetal growth. The prognosis for most fetuses with large CCAMs remains quite favorable under careful perinatal management.

Survival after CCAM associated with ascites: a report of a case and review of the literature

A congenital cystic adenomatoid malformation (CCAM) is a congenital lung lesion that, when associated with hydrops, is thought to have a dismal prognosis without fetal intervention. The authors report a case of a fetus with a CCAM associated with ascites as the only manifestation of hydrops, which was diagnosed at 19 weeks gestation. The CCAM regressed without intervention between 23 and 29 weeks of gestation with resolution of the ascites. The baby was born asymptomatic at term, and the infant underwent elective resection of the CCAM at 1 year of age. A review of the literature from 1980 to 2000 yielded 9 other cases of spontaneous resolution of hydrops associated with CCAM, suggesting that although rare, this outcome is a possibility in fetuses diagnosed with the condition. Because most fetuses diagnosed with hydrops undergo termination of pregnancy, the true incidence of hydrops resolution is potentially higher than predicted. This has important implications for prenatal counseling particularly in centers in which fetal intervention is not available.

Prenatal sonographic diagnosis of laryngeal atresia in association with single umbilical artery

Congenital laryngeal atresia is an extremely rare anomaly that in most cases is incompatible with life. About 50% of cases involve other major malformations. Prenatal sonographic diagnosis of this condition has been described only 6 times. We present a case in which prenatal sonographic examination at 21 weeks' menstrual age revealed enlarged, hyperechoic lungs, dilated upper airways, ascites, and a single umbilical artery. To our knowledge, this is the first reported case of the prenatal diagnosis of laryngeal atresia in association with a single umbilical artery.

Laryngeal atresia presenting as fetal ascites, olygohydramnios and lung appearance mimicking cystic adenomatoid malformation in a 25-week-old fetus with Fraser syndrome

We describe a 25-week-old female fetus of consanguineous parents with ultrasonographic findings of increased echogenicity of lungs mimicking CAM (cystic adenomatoid malformation) type III, olygohydramnios and fetal ascites. A therapeutic abortion was performed and unilateral cryptophthalmos, laryngeal atresia and bilateral syndactyly of the hands and feet were observed at post-mortem. These findings confirmed the diagnosis of Fraser syndrome after abortion.

Fetal lung abnormalities--what do they mean?

Antenatal diagnosis of lung abnormalities by ultrasound has been a much more frequent occurrence in recent years. There is a range of appearances from uniform increased echogenicity through to lesions containing large echo-free areas. Bilateral uniformly increased echogenicity has a poor outlook but in all other situations outcome cannot be accurately predicted from an early second trimester scan. Follow-up through pregnancy often allows a fairly accurate prognosis to be made but the appearance of the lesion does not accurately predict histology. A conservative approach to the antenatal management of unilateral lesions is recommended with long-term postnatal follow-up for all lesions because of the unknown long-term outcome for the lesions, many of which are symptomatic postnatally.

Bronchopulmonary-foregut malformations: a continuum of paracrine hamartomas?

The bronchopulmonary-foregut malformations (BPFM) are usually sporadic, solitary cystic hamartomas involving conducting airways, arteries, venous drainage, and lung parenchyma. Transitional, compound hamartomas exist, and only their morphology is well-known. Between 1984-1994 we encountered and studied 10 unrelated patients and a stillborn infant with BPFM (out of 24,000 families). Ten were diagnosed in utero and one at birth as having congenital cystic adenomatoid malformation of the lung (CCAML). Postnatally, two diagnoses (20%) were corrected to bronchogenic cyst (BC) and diaphragmatic hernia, respectively. Bilateral lung involvement was present in 1 patient, and in 2 there was a considerable macroscopic regression of the hamartoma. Histologic studies of the six resected CCAML confirmed the diagnosis and implied dysregulated paracrine growth with its cellular and extracellular growth factors, protooncogenes, oncogenes, cytokines, cell-adhesive molecules, and receptors of these regulatory peptides, and their complex interactions as developmental morphogens in time and space.

Prenatal sonographic diagnosis of upper airway obstruction: a challenge that can be achieved

Congenital upper airway obstruction presents a life-threatening situation when encountered in the delivery room. We present a case in which in utero diagnosis of this malformation was suspected, but unfortunately the neonate did not survive due to the inability to provide adequate ventilation. The prenatal sonographic features of this rare malformation are outlined, and the literature reviewed.

The prognostic factors in the prenatal diagnosis of the echogenic fetal lung

The prenatal diagnosis of an echogenic fetal lung (EFL) is now often made in the early second trimester using high-resolution ultrasound. This ultrasound appearance is usually caused by a congenital cystic adenomatoid lung malformation (CCAM), an intrapulmonary lung sequestration or obstruction of a major airway. In order to provide prognostic guidelines to parents who may be considering termination of a fetus with these findings, we have analysed a series of 11 cases diagnosed in our centre over the past 2 years in conjunction with 60 cases from major published series. The data suggest that in the absence of non-immune hydrops fetalis (NIHF) or other anomalies, the outcome for the fetuses is excellent, with over 90 per cent survival. Neither early diagnosis (24 weeks) nor the presence of mediastinal shift is a poor prognostic indicator. In addition, it appears that if NIHF is absent at diagnosis, the chance that it will develop as the pregnancy continues is small (6 per cent). Furthermore, there is a significant (up to 30 per cent) chance that this ultrasound finding will resolve in utero. The development of in utero fetal surgical techniques may be the only hope for those hydropic fetuses who appear to have a dismal prognosis.

Successful outcome with serial amniocenteses for polyhydramnios complicating cystic adenomatoid malformation of the lung

Hydrops fetalis secondary to congenital cystic adenomatoid malformation of the fetal lung is almost invariably a lethal condition. This poor prognosis may be attributed to the combined effects of tissue compression from the thoracic space occupying lesion and premature delivery of a hydropic baby following rupture of the membranes in the presence of polyhydramnios. We describe a successful outcome with serial amniocenteses. Partial in utero resolution of the lung lesion with complete return to normal of the aberrant liquor volume was documented, and a live infant was delivered at term.