Ex-Utero Intrapartum Treatment for a Fetal Cervical Teratoma with Mediastinal Extension: A Case Report

Abstract

Patient: Female, 29-year-old

Final Diagnosis: Fetal cervical teratoma at 35 weeks

Symptoms: Polyhydramnios

Clinical Procedure: Ex utero intrapartum treatment tumor excision

Specialty: Pediatrics and Neonatology Surgery

Objective: Congenital defects/diseases

Background

Ex-utero intrapartum treatment (EXIT)-to-airway is a complex perinatal procedure performed in the case of potential postnatal airway obstruction. It requires an experienced multidisciplinary team and meticulous surgical planning based on fetal imaging. This report describes the use of EXIT-to-airway for a large cervical teratoma with extension into the mediastinum.

Case Report

At 35 weeks’ gestation, a 29-year-old woman presented to our fetal care center with significant polyhydramnios. The fetus was subsequently diagnosed with a large cervical mass extending into the mediastinum. An EXIT-to-airway procedure was performed at 36 weeks’ gestation. The neonate remained intubated while postnatal imaging was obtained. At day of life 3, resection of the teratoma was performed via a combined cervical and mediastinal approach. Pathology confirmed a mature teratoma. The neonate’s hospital course was complicated by aspiration with feeding, requiring a gastrostomy tube, and she was discharged on day of life 40.

Conclusions

While cervical teratoma is a well-established indication for the EXIT procedure, this case is notable for its late third-trimester diagnosis and the rare extension of the mass into the mediastinum, which necessitated a dual surgical approach. It highlights the importance of maintaining a broad differential diagnosis in the setting of recurrent third-trimester polyhydramnios and demonstrates the critical role of multidisciplinary planning in optimizing outcomes when airway compromise is anticipated. This case contributes to the growing body of evidence supporting the expanded utility of EXIT-to-airway for complex cervicomediastinal masses.

Introduction

The ex-utero intrapartum treatment (EXIT) procedure is performed for pregnancies with prenatally diagnosed anomalies that may complicate neonatal oxygenation upon delivery. Such anomalies include oral or neck masses, micrognathia, and congenital high airway obstruction syndrome (CHAOS) [1,2]. Among congenital cervical masses, teratomas are the most common; however, mediastinal teratomas are exceedingly rare, comprising only 10% of all cases, with an overall estimated occurrence of ~1: 20 000–40 000 live births [3,4].

Mature teratomas are generally benign and consist of well-differentiated tissues from all 3 germ layers – ectoderm, mesoderm, and endoderm – often including elements like skin, cartilage, or respiratory epithelium. Immature teratomas contain incompletely differentiated or embryonic-type tissues, particularly neuroepithelial components, and their malignant potential correlates with the degree of immaturity. Yolk sac tumors are far more aggressive and have a much higher malignant potential. Proper histologic classification is essential for guiding prognosis and postnatal management [5,6]. Most teratomas are isolated, often midline, lesions and can be cured with surgical excision. However, these tumors are often firm and, when located within the neck or mediastinum, the neonatal airway can become compromised. For this reason, an EXIT-to-airway may be the preferred mode of delivery to avoid hypoxia, anoxic brain injury, and acidosis in the neonate [7–9]. Although several cases of EXIT-to-airway have been reported, the objective of this unique case report is to provide the framework and rationale behind timing of delivery, mode of delivery, and approach to resection for a larger cervical teratoma with complex thoracic extension diagnosed within the third trimester.

Case Report

A 29-year-old gravida 4 para 2 woman presented to Maternal-Fetal Medicine (MFM) at 34 weeks’ gestation for evaluation of idiopathic severe polyhydramnios. The patient’s past medical history, including family history, psychosocial factors, and genetic history were noncontributory. Her obstetric history included a spontaneous abortion at 13 weeks and 2 prior vaginal deliveries. All prenatal ultrasounds were normal, and her current pregnancy course was routine. Additionally, findings on physical exam were unremarkable. Fetal ultrasound (US) at the time of presentation demonstrated a significant amniotic fluid index of 52 without underlying anatomical defects, and a 2-liter amnioreduction was performed. The patient was then discharged in stable condition. One week later, at 35 weeks’ gestation, she presented with re-accumulation of amniotic fluid and was referred to the Colorado Fetal Care Center (CFCC). A repeat fetal US demonstrated a large, complex heterogeneous right-sided cervical mass with extension into the mediastinum, suspicious of teratoma, as shown in Figure 1. Fetal magnetic resonance imaging (MRI) further characterized the lesion with findings consistent with mature teratoma, including cystic and solid portions without fatty infiltration. The mass measured a maximum of 4.9 cm in greatest diameter in the cervical region and 9.6 cm in greatest diameter within the mediastinum. There was mass effect compromising the fetal airway: the cervical trachea was compressed and progressively narrowed until it was 2 mm in diameter within the thorax, with the carina and right mainstem bronchus poorly visualized (Figure 2). The right lung appeared severely compressed due to mediastinal shift with a total lung volume of 26 mL. There was no evidence of pleural effusion. Following the evaluation, the patient was admitted and a 4-liter amnioreduction was performed.

Figure 1. Fetal ultrasound.

Fetal ultrasound performed at 35 weeks’ gestation demonstrating a cervical mass with extension into the right thoracic cavity. There was no evidence of compression of the great vessels or fluid accumulation within the fetus, including pleural effusion or head/scalp edema, indicating the fetus had not developed nonimmune hydrops. (A) Sagittal view demonstrating cervical (yellow arrow) and thoracic (blue arrow) extensions of the tumor. (B) Axial view of the cervical component (yellow arrow). (C) Axial view of the thoracic component (blue arrow).

Figure 2. Fetal MRI.

Fetal MRI performed at 35 weeks’ gestation confirmed the presence of a large, complex solid and cystic mass in the right cervical region and right anterior chest. The lesion appears to be compressing the right lung and trachea, causing airway narrowing (green arrow), mass effect, and mediastinal shift (A). Total fetal lung volume measured by MRI was 26.6 mL (B).

A multidisciplinary team, including MFM, Pediatric and Fetal Surgery, Pediatric Otolaryngology, Pediatric Cardiothoracic Surgery, Fetal Anesthesiology, and Neonatology, met to discuss timing and approach to delivery, airway management, and surgical resection. This mass presented several airway concerns: 1) the degree of airway compression may not be responsive to non-invasive ventilatory techniques, 2) the mass effect on the trachea may compress traditional endotracheal tubes, and 3) traditional alternative airway management strategies (eg, tracheostomy) would not relieve the obstruction caused by long-segment airway compression. Based on this evaluation, the imaging findings, the patient’s late presentation, and the rapid re-accumulation of amniotic fluid, the decision was made to proceed with EXIT-to-airway at 36 weeks’ gestation to allow maximal time for fetal lung maturity but mitigate the risk of premature rupture of membranes and development of nonimmune fetal hydrops. While we were fortunate not to need such resources, Pediatric Cardiothoracic Surgery and our Extracorporeal Membrane Oxygenation (ECMO) Team were present in the delivery room. If the neonate had significant cardiorespiratory instability, the plan was to perform an EXIT-to-resection with emergency median sternotomy to decompress the right chest and improve ventilation, or to perform ECMO via central cannulation (given the right cervical vessels were not accessible due to the tumor location).

In the delivery room, a Pfannenstiel incision was made and an Alexis wound protector was placed. Using ultrasound, we mapped the fundal placenta. Given the recurrence of polyhydramnios, we were able to find a sufficient area in the lower uterine segment to enter the uterus. Atraumatic vascular clamps and uterine staplers were used to make the hysterotomy, and the head and chest were delivered. An intramuscular fetal cocktail, including 20 μg/kg fentanyl, 2 mg/kg rocuronium, and 20 μg/kg atropine with an estimated fetal weight of 3 kg based on the most recent ultrasound, was administered as an adjunct to maternal inhaled anesthetics. Pediatric Otolaryngology performed a rigid bronchoscopy and the fetus was successfully intubated with a 3.0 wire-reinforced uncuffed endotracheal tube. Laryngoscopy was uncomplicated but the distal airway appeared compressed and edematous. With a secured airway, the umbilical cord was clamped and cut, and the neonate was delivered and resuscitated by the Neonatal Intensive Care Unit (NICU) team. The total procedure time from maternal skin incision to securing the fetal airway was 70 minutes. At birth, the female infant appeared healthy, in no acute distress, and weighed 3080 g. The previously identified mass was partially exophytic and mobile within the right-central neck. Neurological status was appropriate for age, and she was maintained on high-frequency oscillatory ventilation without evidence of high-output cardiac failure or overt pulmonary hypertension. Both maternal and fetal vital signs were closely monitored throughout the procedure and remained within normal limits. During the procedure, the estimated maternal blood loss was 100 mL. The maternal hospital course and recovery were uneventful, and she was discharged on postoperative day 4.

The neonate was monitored in the NICU and remained in critical but stable condition for 3 days. During that time, further surgical planning occurred with postnatal imaging. A CT arteriogram of the neck and chest demonstrated a bilobed tumor, 1 lobe in the right cervical region and 1 within the anterior-right mediastinum, with a small bridging stalk connecting them through the thoracic inlet (Figure 3). Surgical planning included Otolaryngology for excision of the cervical portion of the tumor and Cardiothoracic Surgery to excise the thoracic extension.

Figure 3. Postnatal CT arteriogram of neck and chest.

CT Arteriogram of the neck and chest obtained on day of life 1 to aid in surgical planning demonstrated the nonvascular large solid/cystic lesion spanning from the right neck caudally through the thoracic inlet and into the right chest. (A) Axial view of the thoracic component, (B) Coronal view demonstrating the tumor’s bilobar features, (C) Sagittal view illustrating the tumor protruding through the thoracic inlet.

In the operating room, Otolaryngology began the procedure by mobilizing the tumor through a right cervical incision. The narrow stalk of the tumor was found at the thoracic inlet and was divided. Pediatric Cardiothoracic Surgery then performed a median sternotomy. The right lung immediately showed improved expansion after the tumor was removed from the thorax. Bronchoscopy was then performed to visualize the trachea and mainstem bronchi, which demonstrated minimal narrowing, and the neonate was reintubated with a 3.0 microcuff endotracheal tube and transported to the Pediatric Cardiac Intensive Care Unit in stable condition. Both lobes of the tumor were sent to Pathology, which confirmed a mature teratoma.

The neonate was successfully extubated on postoperative day 7 and weaned to room air. A bedside laryngoscopy was performed, which demonstrated normal bilateral vocal fold mobility. The patient’s postoperative course was complicated by difficulty with oral feeding. A swallow study was performed at 30 days of life, which was significant for aspiration with both thin and slightly thick liquids. A laparoscopic gastrostomy was performed for durable enteral access on day of life 37, and the patient was discharged home on day of life 40. Follow-up with repeat MRI at 3 months of age demonstrated no residual or recurrent disease. A detailed clinical timeline is provided in Figure 4.

Figure 4. Clinical course timeline.

A timeline of the clinical course beginning with patient presentation to discharge of neonate at 40 days of age. CFCC – Colorado Fetal Care Center; MFM – Maternal-Fetal Medicine; CTA – Computed Tomography Angiogram; EXIT – Ex-utero Intrapartum Treatment.

Discussion

We present a unique case of a pregnancy with normal first and second trimester fetal imaging, presenting in the third trimester with marked polyhydramnios. The fetus was subsequently diagnosed with a large cervical teratoma with extension into the mediastinum, compressing the trachea at the carina and right mainstem bronchus. Following a successful EXIT-to-airway procedure, the neonate underwent surgical resection with negative margins.

In a high-volume fetal care center, it is not uncommon for our team to evaluate and manage fetal cervical lesions. Differentials for such lesions predominantly include teratoma and cystic hygroma, but more rarely can include lymphangioma, neuroblastoma, hemangioma, goiter, or a soft-tissue tumor [7]. While US is typically diagnostic, MRI is an adjunct to better visualize the extent of the tumor with respect to surrounding structures, such as the lungs, trachea, and great vessels [2].

On MRI, teratomas are typically a heterogenous mix of solid and cystic structures, and calcifications seen within the tumor are nearly pathognomonic. Cystic hygromas and other neck masses are often not solid and have well-defined fluid-filled septations [7]. In our practice, we rarely perform EXITs for cervical lymphatic and vascular anomalies as those lesions are easily compressible, and an endotracheal tube can often be placed without difficulty. We typically consider an EXIT procedure to be more appropriate for cases of severe micrognathia and cervical teratomas that have a dominant solid component [7,10,11]. Although in this case the tumor had cystic components, some portions were solid, particularly in the thorax, calling into question the tumor compressibility for postnatal intubation. Fetal imaging showed the tumor compressed surrounding structures, including the esophagus. A small stomach, combined with severe polyhydramnios, emphasized the degree of esophageal compression and further supported the utility of an EXIT procedure [2,10,12]. These features – polyhydramnios and airway compression – are recognized as adverse prognostic indicators in cervical teratomas [4]. For teratomas with mediastinal extension, additional prognostic considerations include pulmonary hypoplasia and cardiovascular compromise, with nonimmune fetal hydrops representing a particularly poor prognostic marker [13].

While an EXIT procedure was our preferred approach in this case, many options for intervention were discussed during delivery room planning, including delayed cord clamping and the various EXIT procedures, including EXIT-to-airway, EXIT-to-resection, and EXIT-to-ECMO. While a cesarean section with delayed cord clamping may have sufficed, this approach would have provided insufficient time if a surgical airway had been necessary, putting the neonate at risk of hypoxic injury and acidosis [7–9]. The timing of the anomaly’s detection was an important factor in our decision to proceed with EXIT-to-airway. The mass was first identified at 35 weeks’ gestation, without evidence of nonimmune fetal hydrops. By this stage, aerodigestive tract development was largely complete, suggesting that the mass originated in the cervical region and subsequently extended into the mediastinum. This pattern supported the hypothesis that the tumor was causing external compression rather than intrinsic airway malformation. Despite near-complete airway obstruction – extending from just below the vocal cords to the carina – fetal imaging indicated preserved lung development, further supporting the feasibility of securing the airway via EXIT.

Although considered benign, teratomas can be life-threatening due to airway compromise, and have the potential to grow quite large, extending into surrounding structures. The mediastinal extension adds another level of complexity to this case, as the tumor compressed the right lung. The possibility of lung hypoplasia could have impaired the neonate’s ability to oxygenate and ventilate. This observation made delivery planning more complex and required additional members of our team to be present, including Pediatric Cardiothoracic Surgery.

Further complexity arises from the overall nature of fetal surgical procedures, with treatment involving 2 patients – both mother and fetus. Pregnant women have been referred to as “innocent bystanders” in fetal surgery since the intervention does not provide direct medical care to the mother while potentially exposing her to significant risks [14]. Several risks include maternal hemorrhage, uterine atony, placental abruption, anesthesia-associated hypotension, amniotic fluid embolism, and hysterectomy [12,14]. In our case, we utilized tocolytics during the procedure, performed ultrasound guided hysterotomy with uterine staples, and gave uterotonic agents at the conclusion to minimize such risks, particularly related to blood loss. To balance the risks and benefits of an EXIT, its use should be limited to congenital anomalies anticipated to pose significant challenges at the time of delivery.

While there are numerous reports of large cervical teratomas diagnosed prenatally [6,9,12,14–17], there are relatively few that describe mediastinal teratomas or cervical teratomas with intrathoracic extension. Giancotti et al provided a comprehensive summary of the literature on mediastinal teratomas, noting that only 4 reported patients survived [13]. Many of these cases were complicated by nonimmune fetal hydrops, which may be attributed to the significantly larger tumor size compared to our case. Notably, survival was particularly poor among those diagnosed postnatally, underscoring the critical importance of prenatal detection. Our case bears similarity to that described by Dumbell et al, in which a mediastinal mass was diagnosed prenatally at 35 weeks [18]. Their patient underwent spontaneous labor at 36 weeks, followed by immediate neonatal intubation and tumor resection within the first 2 days of life. Although their case occurred in 1990 and did not involve an EXIT procedure, the timing of diagnosis and surgical intervention were comparable to ours. Finally, Merchant et al discussed the likelihood of esophageal compression in cases of anterior mediastinal masses and the associated development of polyhydramnios late in pregnancy [3]. This supports our conclusion that the mediastinal component of the tumor, rather than the cervical portion, was the primary contributor to the polyhydramnios and likely explains the late gestational timing of diagnosis, which followed evaluation for recurrent, unexplained polyhydramnios.

Conclusions

The utility of EXIT-to-airway provides a controlled environment where airway stabilization can occur while the fetus remains oxygenated through the feto-placental circulation. While there are many reports of the use of EXIT for cervical lesions, we present a rare case of cervical teratoma with mediastinal extension and airway compression. This rare case is an example of a successful EXIT-to-airway procedure that was carefully planned with the assembly of a multidisciplinary team.