Rapidly enlarging neck mass in a neonate causing airway compromise

Abstract

Up to 20% of all congenital pediatric head and neck masses are branchial cleft cysts. Second branchial cleft cysts account for 95% of branchial anomalies, and fourth branchial cleft cysts are the rarest type. Their typical presentations include non–life-threatening symptoms, such as drainage, skin irritations, minor swelling, and tenderness. We describe a 5-week-old neonate with increasing stridor secondary to a rapidly growing neck mass. Imaging and surgical excision confirmed the mass to be an infected fourth branchial cleft cyst.

We describe a neonate with a neck mass causing airway compromise. Branchial cleft anomalies comprise up to 20% of all congenital pediatric head and neck lesions (1). Branchial cleft anomalies form when there is an abnormality in the obliteration of the clefts in between the branchial arches (2). Of these anomalies, fourth branchial cleft anomalies are rarest and are typically found in the lower third of the neck on the left side (2, 3). Discovery often occurs after infection of the cyst and resultant suppurative thyroiditis (4). Fourth cleft cysts have been reported to occur at any age, including in utero. Typically, branchial cleft cysts have non–life-threatening symptoms including drainage, skin irritation, minor swelling, and tenderness, but if infected can result in difficulty swallowing and breathing due to mass effect.

CASE DESCRIPTION

A 5-week-old neonate was brought to the emergency department with difficulty breathing and a left-sided neck mass. The mother reported that the infant had increased difficulty breathing at night and when crying for the past 1 week. He also had vomiting for 1 week with decreased appetite. The mass had been noticed 4 weeks earlier and had been progressively increasing in size. The child was alert and comfortable at rest in the mother's arms. However, when placed supine, he became agitated and exhibited stridor and respiratory distress. A 5 × 4 cm mass was identified on the left side of the neck, crossing the midline (Figure 1).

Figure 1.

Five-week-old with mass in left side of neck and resulting rightward shift of the trachea.

An ultrasound of the neck showed a mass with heterogeneous echogenicity with predominantly solid components and minimal vascularity (Figure 2). Computed tomography (CT) of the neck with intravenous contrast demonstrated a nonenhancing mass in the left side of the neck at the base with involvement of the left lobe of the thyroid gland as well as significant compression of the trachea (Figure 3). The mass was excised, and histologic study disclosed it to be a fourth branchial cleft cyst.

Figure 2.

Ultrasound shows a solid mass in the left side of the neck with minimal vascularity.

Figure 3.

CT of the neck shows the mass involving the left lobe of the thyroid gland along with mass effect and rightward displacement of the trachea.

DISCUSSION

When presented with a neck mass in a neonate, differentials include rhabdomyosarcoma, teratoma, venolymphatic malformations, fibromatosis colli, and a branchial cleft cyst. Venolymphatic malformations are typically soft, compressible, and nonpulsatile. Clinical findings are nonspecific in the other differentials.

Ultrasound and CT imaging were helpful in diagnosis. While ultrasound has a low predictive power for third or fourth branchial cleft anomalies, ultrasound imaging in this case was used to eliminate venolymphatic malformations and fibromatosis colli from the differential diagnosis (5). CT is the most common diagnostic tool for branchial anomalies, with a positive branchial anomaly identification rate as high as 64% (5–9). In this case, CT imaging was useful in determining the extent of the mass and identified structures at risk during excision. It also showed the involvement of the left lobe of the thyroid gland.

Treatment of branchial cleft cysts is complete excision after infancy, to prevent recurrent infection and abscess formation as well as mass effect on local structures (10–12). Airway compromise and respiratory distress are indications for emergent surgery. This case illustrates that fourth branchial cleft cysts can rapidly increase in size and compromise the airway and should be considered in the differential diagnosis while evaluating a neonatal neck mass.