Neonatal airway obstruction due to a massive lingual foregut duplication cyst

Abstract

Foregut duplication cysts (FDCs) are rare malformations arising along primitively derived alimentary tract. Head and neck cases comprise 0.3% of all FDCs with 60% occurring in the oral cavity. We present a case of neonatal airway obstruction secondary to a prenatally diagnosed massive lingual FDC. Definitive treatment requires surgical excision. Histologically, the cysts are lined gastric and respiratory epithelium. FDC should be a consideration in prenatally diagnosed masses affecting the oral cavity.

Background

Foregut duplication cysts (FDCs) are rare congenital malformations arising along the primitively derived alimentary tract during the first trimester.^1–3 They account for one-third of all duplication cysts and can be found anywhere from mouth to anus. Because of the varied anatomic locations, no single theory exists to explain the development of FDC. However, it has been proposed that a split notochord may allow a connection between endoderm and ectoderm.³ The most common sites are the thorax and abdomen.^{1 3} The gender distribution for FDCs is not well established. Conflicting evidence reports a gender predilection,² however, a preponderance of bronchopulmonary FDCs occur in women.³ The overall incidence rate of FDCs is 1 in 4500.^{1 4} Head and neck FDCs are very rare and comprise only 0.3% of cases with 60% of cases occurring in oral cavity; most commonly involving the tongue.⁵ Here we present and discuss management of a case of airway obstruction caused by a large tongue FDC initially noted on prenatal imaging.

Case presentation

A G4P2 mother underwent a prenatal anatomic ultrasound (US) significant for a 4×3 cm multiseptated mass protruding from the oral cavity. Second and third trimester fetal MRI demonstrated a 3.5×2.5×2 cm mass (figure 1) with progression from cystic to solid components concerning for teratoma over lymphatic malformation in differential diagnosis. During the prenatal course mild fluctuating polyhydramnios was noted. After a multidisciplinary discussion, decision was made to defer an ex utero intrapartum treatment (EXIT) procedure in favour of an otolaryngology attended delivery.

Figure 1.

(A) Second trimester fetal heavily weighted T2 MRI showing a primarily cystic mass involving the oral cavity (white arrow). (B) Third trimester fetal MRI showing a 3.5×2.5×2 cm mass protruding from the oral cavity (black arrow) with solidification of the intrinsic tongue component.

Attended delivery of a 3.1 kg male infant at 38 weeks was uneventful. The neonate was adequately mask ventilated. Following placement of an umbilical line, microlaryngoscopy and bronchoscopy was performed a demonstrating a large submucosal mass involving the floor of mouth and tongue (figure 2). The base of tongue and larynx were normal in appearance. To secure the airway, the neonate was intubated trans-nasally with 3.0 micro-cuff endotracheal tube. He remained stable throughout the resuscitation and was transferred to neonatal intensive care unit.

Figure 2.

Large submucosal mass involving the oral tongue.

Investigations

On day of life (DOL) two, US of the tongue was performed showing an interconnected bilobed cystic lingual mass containing mobile debris (figure 3). The anterior and posterior lobes of the mass measured 3.0×1.4×2.4 cm and 1.5×1.2×1.6 cm, respectively. Serial alfa-fetoprotein elevated commensurate with perinatal life reducing concern for teratoma. On DOL three, an incisional biopsy of the cyst wall and aspiration of fluid was performed through a ventral tongue incision. Histology revealed a squamous-lined cyst most consistent with epidermoid cyst. Cytology showed nucleated and anucleated squamous epithelial cells.

Figure 3.

Ultrasound showing an interconnected bilobed cystic lingual mass containing mobile debris.

Treatment

On DOL seven, he underwent excision of a bilobed cystic structure via partial glossectomy through a ventral tongue incision (figure 4). Gross pathology revealed two cystic structures measuring 2.8×2.5×1.3 cm and 2.5×1.5×0.7 cm banded together via a 0.5×0.3×0.2 cm soft tissue bridge. Histologically, the cyst had a smooth muscle capsule and contained gastric and ciliated respiratory epithelium consistent with FDC (figure 5). The cyst was resected in entirety. Much of the tongue intrinsic musculature was replaced by the cyst. The residual muscles of the ventral and dorsal tongue were reapproximated and mattress sutures were placed through the tongue to eliminate seroma formation. He did develop oedema of the tongue and an ileus following surgery, but was successfully extubated on postoperative day eight. Given the size of the tongue during development he maintained an open bite deformity and feeding was difficult secondary to labial closure. A gastrostomy was ultimately placed and he was discharged on DOL 38.

Figure 4.

Intraoperative view of bilobed cystic structure excised through ventral tongue incision.

Figure 5.

Histology showing non-keratinising squamous epithelium (white arrow) lining the cyst capsule and surrounding skeletal muscle of the tongue (black arrow).

Outcome and follow-up

At 8 months of age, there is no evidence of recurrence. He persists with mild protrusion of the tongue and significant open bite deformity. The tongue is mobile laterally and protrudes well. He feeds using a bottle and stage 1 baby foods using the gastrostomy two times per day for supplementation.

Discussion

Congenital oral tongue masses are uncommon. The differential diagnosis in this case included lymphatic malformation and teratoma, but consideration of dermoid cyst, thyroglossal duct cyst and other benign and malignant neoplasms such as myofibroma and rhabdomyosarcoma is prudent. Head and neck FDCs are rare phenomenon mostly involving the tongue. Although symptoms may vary, most FDCs are asymptomatic.⁵ The most profound symptoms are antenatal airway distress secondary to a large oral cavity mass as reported here. Although oral cavity FDCs have been well established, there are rare reports of prenatal diagnosis on screening ultrasound. Airway distress at birth has been reported in two prior cases; one due to a tongue mass and the other due to hypopharyngeal mass.^{5 6} Airway distress has also been reported later in life. A review of 22 head and neck FDCs by Kieran et al describes a 2-month-old infant with respiratory distress due to an FDC within the vallecula requiring intubation.¹

Three pathological criteria for FDC include: (1) epithelium derived from the foregut, (2) smooth muscle cyst capsule, (3) attachment to the foregut.¹ Given these lesions are derived from the primitive foregut, epithelium is gastric, intestinal and/or respiratory.² Most lesions are lined with gastrointestinal epithelium.⁷

US is the preferred imaging modality for prenatal screening; however, fetal MRI offers better evaluation of internal characteristics.⁷ Although MRI is not specific for FDC, it is pertinent for the assessment of the location and extent of airway compression/obstruction.⁸ The entirety of the oral cavity, oropharynx, hypopharynx and trachea can be assessed on midsagittal plane on MRI.⁷ The presence of T2 hyperintense signal in the posterior pharynx portends a patent airway after birth.

The keys to airway management include prenatal diagnosis, involvement of a multidisciplinary team and stepwise planned intervention. Complete airway obstruction is hallmarked by progressive polyhydramnios preventing fetal swallow. In this condition, an EXIT procedure should be considered. This mother was identified to have mild and fluctuating polyhydramnios and an EXIT was deferred in favour of an attended delivery. Following delivery ventilation with bask mask and a laryngeal mask airway was confirmed. These steps are critical not only for securing the airway at delivery, but for management in the event of incidental extubation. Microlaryngoscopy revealed a grade 1 view of the glottis. If intubation is not feasible due to limited access from the mass, needle aspiration to decompress the mass can be performed to improve visualisation. Preparation for emergent tracheostomy is requisite for intubation failures.⁹

Definitive curative treatment for FDC is accomplished via surgical resection. Cyst aspiration is palliative alone.² Given FDC is benign and has no potential for malignancy, observation may be feasible in selected cases of small cysts. However, observation carries the risk of infection, haemorrhage, ulceration and dysarthria.^{2 5} FDC should be a consideration in prenatally diagnosed masses affecting the oral cavity.

Learning points.

• Foregut duplication cyst should be a consideration in prenatally diagnosed masses involving the oral cavity.

• Prenatal MRI is useful in assessment of the location and extend of airway compression/obstruction.

• The keys to airway management in a neonate with oral mass include early prenatal diagnosis, involvement of a multidisciplinary team and stepwise planned intervention.

• Microlaryngoscopy and bronchoscopy should be done at birth to assess and secure the airway.