Congenital head and neck masses: What is growing on my child's neck?

By Robert Chun, MD

One of the most distressing things for any parent is to find a head or neck mass on their child. While infections remain the most common etiology for any pediatric head and neck mass, congenital lesions also make up a large proportion of these masses. Although many congenital neck masses present at birth, they actually can appear at any age. One of the easier ways to form a differential diagnosis for these lesions is to separate them by their anatomical location: lateral versus midline neck lesions.

What if the mass is in the lateral neck?

Branchial anomalies: At four weeks' gestation, head and neck structures develop from five or six pairs of branchial arches with associated clefts and pouches. These arches contain ectodermal, mesodermal and endodermal elements that later will form muscle, cartilage, bone and nervous and vascular structures of the head and neck.

One of the more confusing points is the differentiation between a branchial cleft cyst, sinus or fistula. A branchial cyst is a tract without an internal or external opening. A branchial fistula is open from the aerodigestive tract to the skin, and a branchial sinus with or without an associated cyst is a remnant of a cleft (external) or pouch (internal) opening.

First and second branchial cleft anomalies are the most common. There are two types of first branchial anomalies. Type I contain only ectodermal elements and appear as a duplication of the external auditory canal. Type II first branchial anomalies contain ectoderm and mesodermal (cartilage) elements. (See Figure 1.) These typically begin as an infection below the angle of the mandible and travel toward the bony cartilaginous junction of the ear. Both first branchial anomalies lie superficial or pass between branches to the facial nerve. (See Figure 2.)

Second branchial anomalies are the most common and lie anterior to the sternocleidomastoid muscle. They usually will bisect the internal and external carotid arteries and end in the tonsillar fossa. These usually present as painless masses but can enlarge after an upper respiratory infection. Third and fourth brachial anomalies are rare, but both have openings into the pharynx, and fourth brachial anomalies have been associated with recurrent thyroiditis.

Other lateral neck masses: A laryngocele is a rare neck mass that can cause respiratory distress in a newborn. It is an air-filled herniation of the saccule of the laryngeal ventricle, which is space between the true and false vocal cords. This herniation of tissue can extend through the thyrohyoid membrane and present as a lateral neck mass. Other lateral neck mass possibilities are thymic cysts (remnant of thymic tissue as it descends from the third pharyngeal pouch to the mediastinum) and a sternocleidomastoid tumor of infancy. The latter requires conservative treatment with complete resolution in 80 to 100 percent of cases.

What if the mass is midline in the neck?

One of the most common midline neck masses is a thyroglossal duct cyst. It is a remnant of the thyroid gland tract as it descends from the foramen caecum of the base of the tongue, through the hyoid bone, and rests to its final position in the lower neck. Thyroglossal duct cysts usually are found in young children but can be present in patients of any age. These can enlarge with upper respiratory infections and typically elevate with protrusion of the tongue. Another midline neck mass is a dermoid cyst. These are benign lesions that can become infected as well but do not elevate with protrusion of the tongue.

A plunging rannula is a pseudocyst of mucus of the floor of the mouth from the sublingual glands. (See Figure 3.) These can descend into the neck through the floor of mouth muscles as well.

Other congenital neck masses

Teratomas are found in newborns and can cause acute respiratory symptoms due to tracheal compression and associated esophageal compression. These usually can be diagnosed antenatally and may require an ex utero intrapartum treatment (EXIT) procedure to establish a safe airway while ensuring uteroplacental gas exchange while on placental support.

A lymphatic malformation is a benign, cystic mass that originates from the same embryonal tissue as lymph vessels. They can occur anywhere in the head and neck and can cause aerodigestive symptoms, especially if they enlarge due to acute infection or hemorrhage into the cystic spaces. Sclerotherapy with Picibanil (lyophilized group A Streptococcus pyogenes incubated with penicillin G) as an alternative to surgery has been shown to be extremely effective in treatment of macrocystic lymphatic malformations. (See Figures 4 and 5.)

Hemangiomas are the most common head and neck neoplasm in children. These may be seen at birth but usually are seen in the first few months of life and enlarge over the next 12 to 18 months until involution. A majority of these lesions will resolve spontaneously. There are multiple medical treatments available, including steroid therapy and chemotherapy with vincristine, and new studies on the use of propanolol have begun. (See Figures 6 and 7.) Furthermore, it must be emphasized that hemangiomas must be differentiated from vascular malformations (arteriovenous malformation, venous malformations, etc.), which will continue to grow with the child and will require more aggressive surgical and medical therapy.

In general, the outcomes from congenital neck masses wherever they may lie are very good. However, prompt diagnosis and management is needed to differentiate these congenital neck masses from infectious or malignant processes.

Robert Chun, MD, is a pediatric otolaryngologist at Children's Hospital of Wisconsin, an assistant professor of Otolaryngology at The Medical College of Wisconsin and a member of Children's Specialty Group.

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