Imaging of fetal tumors and other dysplastic lesions: A review with emphasis on MR imaging

Fetal tumors and other dysplastic masses are relatively rare. They are usually the result of failure of differentiation and maturation during embryonic or fetal life; dysplastic lesions may be the consequence of an obstruction sequence. In this review, we present the most commonly encountered tumors and masses seen during fetal life. Imaging characteristics, tumoral organ of origin, and its effect on the surrounding organs and overall fetal hemodynamics are descriptors that must be relayed to the fetal surgeon and maternal fetal medicine expert, in order to institute most accurate parental counseling and appropriate perinatal treatment plan.

The Use of Fetal Bronchoscopy in the Diagnosis and Management of a Suspected Obstructive Lung Mass

Etiologies of fetal lung anomalies include congenital pulmonary airway malformation (CPAM), intra- or extralobar pulmonary sequestration, congenital high airway obstruction syndrome (CHAOS), bronchogenic cyst, and bronchial atresia. Fetal tracheobronchoscopy has been reported both as a diagnostic and therapeutic procedure in the setting of severe congenital lung lesions. In this case report, prenatal imaging of a fetus with a large chest mass was suspicious for an obstructive bronchial lesion. The absence of visible normal lung tissue on the right side and mass effect on the left side raised the concern for pulmonary hypoplasia. After antenatal betamethasone and a period observation, hydropic changes developed. Fetal tracheobronchoscopy was then performed in an effort to identify and decompress the suspected obstructive bronchial lesion. Other than release of bronchial debris, no anatomical abnormalities were visualized. However, the right lung lesion and mediastinal shift both decreased after the fetal bronchoscopy. The newborn underwent postnatal resection of a CPAM Type II and is doing well. We hypothesize that fetal tracheobronchoscopy provided the following potential diagnostic and therapeutic benefits: (1) exclusion of an obstructive bronchial lesion; (2) disimpaction of bronchial debris from the saline lavage that we posit may have contributed to the rapid reduction in CPAM size.

Airway compromise in the fetus and neonate: Prenatal assessment and perinatal management

The fetus with a potentially obstructed airway can be identified on routine antenatal imaging. These cases should be referred to fetal care centers, which have the necessary expertise to fully evaluate and manage these fetuses and neonates appropriately. Complete airway obstruction may result in fetal hydrops and intrauterine demise. If a newborn infant has a compromised airway at delivery, the inability to secure its airway quickly may result in a hypoxic cerebral insult or death. In the most severely affected cases, prenatal, perinatal, or postnatal surgical intervention may be necessary. The timing of such an intervention will depend on the exact cause of the airway obstruction, other associated findings and the anticipated difficulty in establishing an airway at delivery. Fetal ultrasound and magnetic resonance imaging can differentiate between intrinsic and extrinsic airway obstruction, which allows for the optimal planning and management of the delivery and neonatal resuscitation.

Fetoscopic laser surgery to decompress distal urethral obstruction caused by prolapsed ureterocele

We report on the successful use of fetoscopic surgery to treat a case of prolapsed ureterocele in a female fetus. At 21 weeks' gestation, a double renal system with an intravesical ureterocele obstructing the bladder outlet was diagnosed, causing severe megacystis, bilateral hydronephrosis and progressive oligohydramnios. Ultrasound evaluation following referral to our center confirmed severe bilateral hydronephrosis with pelvic and calyceal dilatation, but amniotic fluid volume was normal and the ureterocele was not visualized in the bladder. Instead, a cystic mass within the external genitalia was observed, suggestive of a prolapsed ureterocele, causing intermittently severe obstruction of the urethra. The parents were counseled about the uncertain prognosis and fetal surgery to decompress the urinary system was proposed. The procedure involved firing a contact diode laser until perforation of the ureterocele was achieved. Following laser surgery, resolution of megacystis, reduction of hydronephrosis and normalization of amniotic fluid volume were observed. Our report demonstrates that fetoscopic decompression of a distal urethral obstruction is feasible in the rare event of congenital prolapsed ureterocele.

Laser Ablation of Posterior Urethral Valves by Fetal Cystoscopy

Objective: To report the results of fetal cystoscopic laser ablation of posterior urethral valves (PUV) in a consecutive series in two referral centers. Methods: Twenty pregnant women with a presumptive isolated PUV were treated with fetal cystoscopy under local anesthesia. Identification and fulguration of the PUV by one or several firing-contacts with diode laser were attempted. Perinatal and long-term outcomes were prospectively recorded. Results: The median gestational age at procedure was 18.1 weeks (range 15.0-25.6), and median operation time was 24 min (range 15-40). Access to the urethra was achieved in 19/20 (95%) cases, and postoperative, normalization of bladder size and amniotic fluid was observed in 16/20 (80%). Overall, there were 9 (45%) terminations of pregnancy and 11 women (55%) delivered a liveborn baby at a mean gestational age of 37.3 (29.1-40.2) weeks. No infants developed pulmonary hypoplasia and all were alive at 15-110 months. Eight (40% of all fetuses, 72.7% of newborns) had normal renal function and 3 (27.3%) had renal failure awaiting renal transplantation. Conclusion: Fetoscopic laser ablation for PUV can achieve bladder decompression and amniotic fluid normalization with a single procedure in selected cases with anyhydramnios. There is still a significant risk of progression to renal failure pre or postnatally.

Fetal Endoscopic Tracheal Intubation: A New Fetoscopic Procedure to Ensure Extrauterine Tracheal Permeability in a Case with Congenital Cervical Teratoma

Congenital neck masses are associated with high perinatal mortality and morbidity secondary to airway obstruction due to a mass effect of the tumor with subsequent neonatal asphyxia and/or neonatal death. Currently, the only technique designed to establish a secure neonatal airway is the ex utero intrapartum treatment (EXIT) procedure, which involves neonatal tracheal intubation while fetal oxygenation is maintained by the uteroplacental circulation in a partial fetal delivery under maternal general anesthesia. We present a case with a giant cervical teratoma and huge displacement and compression of the fetal trachea that was treated successfully at 35 weeks of gestation with a novel fetoscopic procedure to ensure extrauterine tracheal permeability by means of a fetal endoscopic tracheal intubation (FETI) before delivery. The procedure consisted of a percutaneous fetal tracheoscopy under maternal epidural anesthesia using an 11-Fr exchange catheter covering the fetoscope that allowed a conduit to introduce a 3.0-mm intrauterine orotracheal cannula under ultrasound guidance. After FETI, a conventional cesarean section was performed uneventfully with no need for an EXIT procedure. This report is the first to illustrate that in cases with large neck tumors involving fetal airways, FETI is feasible and could potentially replace an EXIT procedure by allowing prenatal airway control.

Fetal bronchoscopy as a useful procedure in a case with prenatal diagnosis of congenital microcystic adenomatoid malformation

Massive microcystic congenital cystic adenomatoid malformation (CCAM) and bronchial atresia are associated with a high perinatal mortality secondary to lung hypoplasia and cardiac dysfunction, and fetal intervention should be considered to improve prognosis. Therapeutic options include open fetal surgery with pulmonary resection, fetal sclerotherapy and fetoscopy. We present a case with a severely enlarged left lung without ultrasound signs of dilated airways compatible with the diagnosis of microcystic CCAM, hydrops and severe contralateral lung hypoplasia that was treated successfully at 30 weeks of gestation by fetal bronchoscopy, through which bronchial atresia was identified at the end of the left mainstem bronchi and permeabilized by laser ablation. After fetal surgery, weekly follow-up showed a progressive decrease in the affected lung size and an increase in the contralateral hypoplastic lung size, demonstrating normal dimensions of both lungs at 34 weeks of gestation, reversal of the mediastinal shift, and complete disappearance of hydrops. A healthy neonate was delivered uneventfully at term with no need for respiratory support, and the boy is now doing well at 15 months of age. This report demonstrates that in cases with prenatal diagnosis of large microcystic CCAM, fetal bronchoscopy can be used to refine the diagnosis of bronchial atresia and as a therapeutic tool with good outcome.

Ex utero intrapartum treatment to resection of a bronchogenic cyst causing airway compression

We present a case report of a 28-year-old primigravida with a singleton pregnancy complicated by a fetal bronchogenic cyst compressing the left mainstem bronchus with resultant hyperinflation of the entire left lung and rightward mediastinal shift. An ex utero intrapartum treatment to resection of the fetal bronchogenic cyst via a fetal thoracotomy was performed at 36 weeks' gestational age, circumventing a potentially complicated neonatal airway emergency at birth.

Tracheo-bronchial angles in the human fetus -- an anatomical, digital, and statistical study

Background

Both the advancement of visual techniques and intensive progress in perinatal medicine result in performing airway management in the fetus and neonate affected by life-threatening malformations. This study aimed to examine the 3 tracheo-bronchial angles, including the right and left bronchial angles, and the interbronchial angle, in the fetus at various gestational ages.

Material/Methods

Using methods of anatomical dissection, digital image analysis with an adequate program (NIS-Elements BR 3.0, Nikon), and statistics, values of the two bronchial angles and their sum as the interbronchial angle were semi-automatically measured in 73 human fetuses at the age of 14–25 weeks, derived from spontaneous abortions and stillbirths.

Results

No male-female differences between the parameters studied were found. The 3 fetal tracheo-bronchial angles were found to be independent of age. The right bronchial angle ranged from 11.4° to 41.8°, and averaged 26.9±7.0° for the whole analyzed sample. The values of left bronchial angle varied from 24.8° to 64.8°, with the overall mean of 46.2±8.0°. As a consequence, the interbronchial angle totalled 36.2–96.6°, and averaged 73.1±12.7°.

Conclusions

The tracheo-bronchial angles change independently of sex and fetal age. The left bronchial angle is wider than the right one. Values of the 3 tracheo-bronchial angles are unpredictable since their regression curves of best fit with relation to fetal age cannot be modelled. Both of the 2 bronchial angles and the interbronchial angle are of great relevance in the location of inhaled foreign bodies, and in the diagnosis cardiac diseases and mediastinal abnormalities.