Nasopharyngeal teratoma causing airway obstruction in the neonate

Abstract

Teratomas are the most common congenital tumours, but teratomas of the nasopharynx are rare in neonates. The present report concerns a premature 30-week-old infant girl with an extensive nasopharyngeal teratoma protruding from the oral cavity. The tumour completely obstructed the airway and necessitated immediate intubation. The tumour was successfully resected directly via the transoral route without needing external incisions. Histological examination of the specimen revealed it to be a mature teratoma. The management and differential diagnosis is discussed, accompanied by a review of the literature.

INTRODUCTION

Teratomas are the most common extragonadal germ cell tumours of childhood, consisting of tissues from at least two of the three germ layers.¹ The incidence of teratomas is 1:4000 births, with the sacrococcygeal area being the most common site.² Teratomas of the head and neck account for less than 2% of reported cases of congenital teratomas, and are most commonly found in the cervical neck.^2–5 An incidence of 1 in 20 000 to 1 in 80 000 live births has been reported and these tumours account for 1.6% to 9.3% of all neonatal teratomas.⁶

Nasopharyngeal lesions are even more rare. A female predominance of 6:1 has been widely reported in the literature.^2,4 Symptoms are dependent on the size and location of the lesion and include respiratory distress, dyspnoea, failure to thrive, difficulty in feeding, or even intermittent symptoms of cough, cyanosis and dysphagia.² Nasopharyngeal teratomas arise from the skull base or the posterior pharyngeal wall and extend inferiorly to cause obstruction of the upper aerodigestive tract. Although some of these tumours are small, others can be large enough to protrude from the oral cavity.⁴

We present a case report of a neonate with a nasopharyngeal mass that was histologically defined as a mature teratoma, and summarise a review of the literature on teratomas of the nasopharynx.

CASE REPORT

A 1400-g infant, the fourth baby of a 30-year-old mother, was delivered by caesarean section because of polyhydramnios at 30-weeks gestation with a red mass protruding from her mouth, causing respiratory difficulty. The mother’s other children had been delivery normally with no congenital malformations. Apgar scores were 4 and 4 after 1 and 5 min, respectively. A nasopharyngeal mass was noted on physical examination, obstructing the upper airway (fig 1). Endotracheal intubation was very difficult but successfully performed, and the child’s airway secured. No associated congenital malformation was detected.

Figure 1.

Mass protruding from the mouth and obstructing the upper airway.

On admission, a CT scan revealed a large pharyngeal ill-defined mass of heterogenous density displacing the endotracheal tube toward the right (fig 2A). There was no sign of bone destruction or intracranial extension. Visualised calvarium and paranasal sinuses were intact. Additionally, three-dimensional volume-rendered CT images were obtained from axial images at a separate workstation (fig 2B). On MRI of the head and neck the mass was noted to have a pedicle, which originated from the left lateral nasopharyngeal wall and the ipsilateral soft palate (fig 3). There was no abnormal intensity change in the brain parenchyma. The lesion showed marked heterogenous enhancement after the administration of gadolinium diethylene triamine pentaacetic acid (Gd-DTPA).

Figure 2.

Preoperative CT scans. A. Non-contrast axial CT image shows a large mass of heterogeneous density with calcification (short black arrows) arising from the nasopharynx. B. Three-dimensional volume-rendered CT image showing a multilobulated, pedunculated mass (long black arrows) protruding from the oral cavity and displacing the endotracheal tube (white arrow) toward the right.

Figure 3.

Sagittal T2-weighted MRI scan demonstrates a heterogeneously large soft tissue mass (short white arrows) arising from the left lateral wall of the nasopharynx and extending through the oral cavity to the exterior without intracranial extension.

The mass was pedunculated and measured 7×3, 5×1 cm, with a stalk, which attached by a narrow base to the left lateral wall of nasopharynx and nasal surface of the soft palate. Under general anaesthesia, transoral excision was performed without needing external incisions. The mass was separated from the soft palate and left lateral nasopharyngeal wall and dissection continued toward the skull base, with bleeding controlled by bipolar electrocautery. There was no evidence of a cerebrospinal fluid leak.

Histological examination of the specimen revealed it to be a mature teratoma. Histological analysis showed fibroconnective tissue, neuroglial tissue, a squamous cell layer, respiratory epithelium, immature tooth and bone lamella. There were no signs of malignancy. After the operation the patient’s general health condition was very good. Because of immature lung function the patient needed ventilator respiration. Ventilator complications of pneumohaemothorax and pneumonia arose, and 3 weeks later the patient died.

DISCUSSION

Neonatal head and neck teratomas are extremely rare. There are less than 300 reported cases of neonatal head and neck teratomas in the literature.⁶ Nasopharyngeal teratomas are rare congenital tumours, which form only a small proportion of head and neck teratomas. They most commonly arise from the midline or lateral nasopharyngeal wall.^2,6

The differential diagnosis of nasopharyngeal masses in the infant includes intranasal glioma, meningoencephalocele, encephalocele, congenital rhabdomysarcoma, haemangioma, neurofibromatosis and lymphatic malformation.² There have been several reports of associated abnormalities occurring with nasopharyngeal teratomas. These include incomplete or complete palatal clefts, cardiac abnormalities, microcephaly and atresia of the left common caroti.² In the case presented, there was no associated congenital malformation detected.

It is sometimes possible to diagnose these tumours in utero. These tumours can produce an elevated maternal α-fetoprotein (AFP), polyhydramnios, and also the mass can be detected on ultrasound scan, although further imaging with MRI is advisable to detect the extent of the lesion.⁴ Prenatal diagnosis allows a carefully planned delivery to maintain an open airway and potentially improve perinatal outcome.¹ Nasopharyngeal teratomas are associated with the presence of polyhydramnios and elevated AFP (in about 20% to 30% of cases, they are associated with polyhydramnios). It thought that when large enough, the tumour obstructs the oesophagus and interferes with prenatal swallowing by the fetus. Our case was associated with polyhydramnios. Polyhydramnios, stillbirth and premature labour are frequent concomitant conditions and some fetuses may be too large for due dates.¹

The major cause of morbidity and mortality is from the size and location of the teratoma, causing airway obstruction and respiratory distress. Respiratory distress was the most common presenting symptom, although patients with teratomas were more likely to require intubation or tracheotomy to secure their airway prior to surgical excision of the lesion. Caesarean section is the preferred method of delivery for infants with an obstructing mass of the head or neck, because airway obstruction can cause severe complications. Immediately before the termination of fetomaternal circulation, these infants should undergo intubation by the oral or nasal route. Some neonates with a huge obstructing mass may require tracheotomy in the delivery room.³

In childhood, 75% to 85% of teratomas of the head and neck region usually contain neuroectodermal elements such as this case.¹ Approximately 80% of teratomas are benign, although malignant lesions have been infrequently described. Congenital teratomas are generally mature in nature. Malignancy is not equated with the degree of immaturity of the tissue elements. This case had no histological evidence of malignancy. Malignant extragonadal teratomas occur in adults and older children but there are also isolated reports of neonatal malignant teratomas.^1,7

Preoperative CT and MRI are imperative to rule out intracranial extension of the tumours.^2,7–9 These imaging techniques aid in demonstrating the relationship of the lesion to surrounding vascular, bony and visceral structures. Before treating any congenital nasopharyngeal mass, the surgeon must ensure that the mass has no relationship to vascular structures in the neck and does not have an intracranial extension or communication.⁷ CT and MRI often show a soft tissue mass filling the nasopharynx and extending inferiorly to involve the oropharynx, hypopharynx and supraglottis to varying degrees. However, in most of these cases MRI was first performed for diagnosis. Because nasopharyngeal teratoma is soft tissue it can be better seen on MRI than CT. These studies may also demonstrate calcification and cystic formation.^2,8,10 In our case, there was no evidence of intracranial involvement.

The recommended management for head and neck teratomas is surgical excision. This is curative and recurrence is rare. These tumours are often encapsulated or pseudoencapsulated and not infiltrating, which facilitates dissection of the teratoma from surrounding tissue structures. When a neonate is experiencing respiratory difficulty, the first priority should be stabilisation of the airway.¹ Our case required endotracheal intubation. Death in neonates usually results from respiratory obstruction due to lesion bulk and location.^1,11,12 Transoral endoscopic removal of lesions located in the nasopharynx has been described, and this approach provides direct visualisation of the mass at its base.¹³ Recurrence of these lesions is rare, and often felt to either be a remnant of the original tumour or a missed secondary lesion as opposed to a true recurrence.² Despite the fact that congenital head and neck teratomas are most often of benign histology, routine follow-up is a necessary. In future follow-up examinations, the patient must be evaluated for recurrence of the tumour by physical examination and flexible nasopharyngoscopy, CT, or MRI when indicated.¹⁴