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Pediatric Neck Masses







Oral and Maxillofacial Surgery Clinics, 2012-08-01, Volume 24, Issue 3, Pages 457-468, Copyright © 2012


The majority of neck masses in the pediatric population are congenital or inflammatory in origin requiring a thorough understanding of embryology and anatomy of the cervical region. However, malignancy must always be ruled out as they represent 11%–15% of all neck masses in the pediatric population. The initial history and physical are of utmost important to correctly work-up and eventually diagnose the lesion. This article addresses many aspects of the workup, diagnosis and eventual proper surgical or medical management of pediatric neck masses.

Key Points

  • Children with neck masses require a thorough clinical examination and follow-up to determine the biological nature and course of the abnormality. Malignancy must always be considered, as it occurs in 11% to 15% of all pediatric cervical masses.

  • Inflammatory disease represents the most common cause of neck masses or lumps in children, with cervical adenitis being the most common entity of the inflammatory processes.

  • The second branchial arch represents about 90% of all branchial cleft/arch-related cysts and sinuses.

  • Cysts of the thyroglossal sinus tract should be preoperatively studied for remnant thyroid tissue along its track of descent from the base of tongue. All thyroglossal sinus tract excisions should include the mid portion of the hyoid using the Sistrunk technique to ensure eradication.


Introduction

Primary care physicians often see a child with a neck mass or an enlarging mass of several weeks’ duration. The possible entities are many; however, it is important to be able to make an early distinction based on history and presentation and to subsequently make an appropriate referral to a pediatric specialist. Depending on the suspected lesion, imaging modalities are obtained to better define the nature and extent of the mass before definitive diagnosis and treatment.

Most neck masses are congenital or inflammatory in origin, although 5% of all pediatric neoplasms occur in the head and neck. The initial investigation must include a very precise history as to time of appearance, duration and changes of the mass, prior occurrence or multiple lesions, associated pain or dysphagia, leakage of fluid from the mass, associated injury, illness or systemic condition, and exposure to animals and travel. A careful examination of the head and neck will help to further narrow the possible etiology. These aspects of the workup and diagnosis of the cervical mass in children are presented in this article, with proper surgical management outlined for each category of lesion.

The differential diagnosis of pediatric neck masses is broad. Although the majority are benign, approximately 1 in 10 of biopsied masses were malignant in a review from the Children's Hospital of Pennsylvania. In this review, Torsiglieri and colleagues examined 445 pediatric neck masses and classified them into congenital, inflammatory, noninflammatory benign lesions, benign neoplasms, and malignant neoplasms.

Not surprisingly, congenital lesions were the most common mass based on Torsiglieri's review, with inflammatory lesions the second most common. However, many inflammatory lesions resolve with conservative therapy and are never removed or biopsied, and are likely the most common pediatric neck mass seen in clinical practice. This review also likely overestimates the frequency of malignant masses, as the Children's Hospital of Pennsylvania is a tertiary care facility for referred complex pediatric patients. However, Torsiglieri's survey provides the most comprehensive review of pediatric neck masses.


Embryology and anatomy

A review of fetal development of the cervical region helps in understanding the nature and pathogenesis of some cervical masses. During the latter part of the third week of craniocervical development, the buccopharyngeal membrane begins to break down into 6 paired pharyngeal arches. The fifth arch is small and disappears in the fourth week. The external surfaces are covered by ectoderm and internally by pharyngeal derived endoderm. Each pharyngeal (branchial) arch contains musculoskeletal, vascular, and neural elements, which contribute to future corresponding entities.

The first arch contains 2 cartilaginous structures: a maxillary process and a mandibular projection known as Meckel cartilage. Lateral ossification around Meckel cartilage forms the mandible, sphenomandibular, and anterior mallear ligaments. The nerve component is the trigeminal (fifth cranial nerve), and the arterial elements give rise to some portions of the internal maxillary artery. The muscles of mastication, tensor palatini and tensor tympani, anterior digastric and mylohyoid musculature, are all derived from the first arch.

The second branchial arch, also called Reichert cartilage, primarily forms musculoskeletal elements: muscles of facial expression, posterior digastric, stylohyoid, stapedius, and platysma muscles, and portions of the hyoid and the styloid process. The facial (seventh cranial nerve) nerve is derived from the second arch. Very little remains of the arterial component except for the stapedial artery.

The third arch gives rise to the remainder of the hyoid, the stylopharyngeus, upper constrictors, and portions of the carotid vasculature. It also forms the inferior parathyroids, thymic duct, and thymus. The cranial nerve is the glossopharyngeal (ninth).

The fourth arch forms the inferior constrictor and cricothyroid muscles. Its nerve is the superior laryngeal, and vascular elements contribute to the right subclavian and on the left, the aortic arch. The superior parathyroids form from the fourth arch.

The remaining sixth arch gives rise to most of the laryngeal intrinsic musculature supplied by the recurrent laryngeal nerve. The arterial portion forms the ductus arteriosus and parts of the pulmonary artery. The fourth and sixth arches fuse to form the laryngeal cartilages.

The thyroid gland forms from descending endoderm at the tuberculum impar at the end of the third week. It travels to and around the developing hyoid bone to take up position in the lower anterior neck.


Background

History and physical examination are paramount in the evaluation of the pediatric neck mass. The history and physical examination produce the differential diagnosis of the mass and often allow the differentiation of lesions into congenital, inflammatory, benign, or malignant, if a definite diagnosis cannot be made.

Certain caveats of the history and physical examination are crucially important. Location helps to narrow down the differential diagnosis. A midline neck mass may represent a thyroglossal duct cyst, dermoid and epidermoid cysts, cervical clefts, or teratomas. Lateral neck masses are more likely to be branchial cleft anomalies, lymphatic or vascular malformations, and thyroid nodules. Congenital anomalies are more likely to present early, whereas malignancies are more frequently encountered in older children.

Neck masses in children can be generally categorized by their location in the cervical anatomy.

  • Anterior Triangle

  • Lymphadenopathy

    • Infectious/Inflammatory: lymphadenitis, mycobacterial

    • Neoplastic: lymphoma, secondary spread

  • Thyroglossal duct cysts

  • Branchial cleft cysts

  • Dermoids and lipomas

  • Thyroid masses (adolescent females), goiter.

  • Posterior Triangle

  • Lymphadenopathy

  • Vascular malformations (lymphatic)

  • Fibromatosis colli (pseudotumor of infancy)

  • Glandular (parotid).

Once the likely cause is determined by history and physical examination, further testing can be used to confirm the clinical suspicion. Laboratory testing, fine-needle aspiration (FNA) biopsy, and imaging of pediatric neck masses are often carried out to further classify the lesion.


Congenital lesions

Congenital masses are the most common noninflammatory neck mass in children. Each type has a typical location and presentation in the neck. Children with congenital malformation of the neck require comprehensive pediatric evaluation to ensure it is not a manifestation of a systemic syndrome, which could modify the treatment plan.


Branchial Cleft Anomalies

During embryologic development, the tissues of the neck are derived from branchial arches that are separated externally by grooves and internally by pharyngeal pouches. Incomplete or aberrant fusion of 2 adjacent arches can result in the formation of branchial cleft anomalies that include cysts, internal sinuses, external sinuses, and fistulas. Anomalies can arise from each embryologic groove and have characteristic locations and anatomic boundaries based on the structures derived from the adjacent embryologic arches.

Cysts arising from the first branchial arch comprise about 8% of cervical sinus tracts and cysts. These cysts often present with recurrent swelling and drainage with secondary infection. Type I first-arch cysts typically open in the preauricular or postauricular region ( Figs. 1–3 ). The sinus tract usually courses parallel to the external auditory canal to the middle ear or deep portion of the cartilaginous canal ( Fig. 4 ). Surgical excision is undertaken when no infection is present.

Categories of neck masses presenting in children.
Fig. 1
Categories of neck masses presenting in children.

Categories of congenital neck masses in children.
Fig. 2
Categories of congenital neck masses in children.

A type I first branchial arch sinus and cyst presenting in the preauricular region. ( A ) Type I fistula ( arrow ) and cystic swelling preoperatively. ( B ) Sinus tract and cyst being delivered from its attachment to the external auditory canal cartilage.
Fig. 3
A type I first branchial arch sinus and cyst presenting in the preauricular region. (
A ) Type I fistula (
arrow ) and cystic swelling preoperatively. (
B ) Sinus tract and cyst being delivered from its attachment to the external auditory canal cartilage.

Pathway of type I first branchial cleft anomalies. EAM, external auditory meatus; SCM, sternocleidomastoid muscle.
Fig. 4
Pathway of type I first branchial cleft anomalies. EAM, external auditory meatus; SCM, sternocleidomastoid muscle.

Type II cysts of the first arch are classically located in the anterior neck, superior to the hyoid. Sinuses course anteriorly to the hyoid, often through and around the parotid and facial nerve, respectively ( Fig. 5 ). Great care must be exercised in the surgical exposure of the area through superficial parotidectomy to avoid damage to the facial nerve.

Pathway of type II first branchial cleft anomalies.
Fig. 5
Pathway of type II first branchial cleft anomalies.

Cysts of the second branchial arch are the most common branchial entity, accounting for about 90% of the cervical cysts. If a skin opening is present, it is found along the anterior border of the sternocleidomastoid muscle ( Fig. 6 ). As the cyst passes into the deep neck, it travels deep and posterior to the submandibular gland and between the internal and external carotid arteries to terminate in the tonsillar fossa ( Fig. 7 ). Imaging to delineate its course and endoscopy to visualize the pharynx for sinus openings are requisites before surgery ( Fig. 8 ).

( A, B ) Second branchial arch cysts in 2 patients, both presenting anterior to the sternocleidomastoid muscle ( arrow ).
Fig. 6
(
A, B ) Second branchial arch cysts in 2 patients, both presenting anterior to the sternocleidomastoid muscle (
arrow ).

Pathway of second branchial cleft anomalies.
Fig. 7
Pathway of second branchial cleft anomalies.

Sagittal ( A ) and axial ( B ) computed tomography (CT) images of a branchial cleft cyst of the left neck.
Fig. 8
Sagittal (
A ) and axial (
B ) computed tomography (CT) images of a branchial cleft cyst of the left neck.

Cysts of the third and fourth branchial arches are uncommon (<2%) and represent sinus tracts, which course deep into the anterior cervical structures and thyroid gland ( Fig. 9 ). Imaging is important, as is endoscopic examination of the pyriform fossa, to identify the internal sinus opening. The unusual presentation of suppurative thyroiditis in children may be due to secondarily infected third- or fourth-arch sinuses.

Pathway of third branchial cleft anomalies.
Fig. 9
Pathway of third branchial cleft anomalies.

Thyroglossal Duct Cyst

Thyroglossal duct cysts are the second most common congenital pediatric neck mass and form as a result of the thyroid's embryologic “journey” to the anterior neck. The thyroid gland begins to develop in the third week in utero at the foramen cecum and then descends into the anterior neck to overlie the larynx. Occasionally, a remnant of embryologic ductal tissue persists following this process and can later develop into an epithelial lined tract ( Fig. 10 ). In fact, the presence of the pyramidal lobe of the thyroid represents failure of closure of the duct at its most inferior location.

Pathway of the thyroglossal duct with depiction of the typical cyst anterior to the hyoid.
Fig. 10
Pathway of the thyroglossal duct with depiction of the typical cyst anterior to the hyoid.

Thyroglossal duct cysts primarily present in the midline, and can occur anywhere between the base of the tongue and the thyroid gland ( Fig. 11 ). The cysts may lie dormant in a similar fashion to branchial cleft anomalies until they become swollen and painful, which can occur after an upper respiratory infection. Clinical diagnosis, based on a thorough history and physical examination, is usually accurate. Thyroglossal duct cysts are most easily seen with the neck in an extended position, and they will elevate with swallowing and tongue protrusion because of their fixation to the hyoid bone.

Thyroglossal duct sinus and cyst. ( A ) Anterior neck of an infant with draining sinus tract ( arrow ). ( B ) Axial CT with contrast showing cystic cavity in fistula ( arrow ). ( C ) Fistulogram of thyroglossal sinus tract extending from tongue base to thyroid.
Fig. 11
Thyroglossal duct sinus and cyst. (
A ) Anterior neck of an infant with draining sinus tract (
arrow ). (
B ) Axial CT with contrast showing cystic cavity in fistula (
arrow ). (
C ) Fistulogram of thyroglossal sinus tract extending from tongue base to thyroid.

During the preoperative evaluation, additional imaging and thyroid uptake studies may be indicated. The best modality of imaging in children is ultrasonography, which can adequately document the presence and configuration of the thyroid gland or any derivatives in the descent route. It is important to confirm the presence of normal thyroid tissue outside of the thyroglossal duct cyst before excision, as well as identification and distinction from lingual thyroid tissue.

Complete excision of a thyroglossal duct cyst is performed by the Sistrunk procedure, first described in 1920. This procedure requires removal of the cyst and any associated tract as well as the middle portion of the hyoid bone. Failure to remove the middle portion of the hyoid bone will often lead to recurrence and infection. Patients at greater risk of recurrence are those with infected, draining sinuses. Excision of sinus, anterior hyoid, and investing scarred infrahyoid musculature may be necessary to achieve eradication.


Dermoid Cysts and Teratomas

The term dermoid cyst is often used in a generic sense to describe 3 separate entities that include epidermoid cysts, true dermoid cysts, and teratomas. These pathologic entities are distinguished by their derivation. Epidermoid cysts arise from ectodermal tissue alone and are normally found superficially in the subcutaneous tissues. Histologically they have a squamous epithelial lining and often contain keratinaceous debris ( Fig. 12 ). True dermoid cysts are composed of both ectodermal and mesodermal components including hair follicles, sebaceous glands, and/or sweat glands.

Cut specimen of a dermoid cyst.
Fig. 12
Cut specimen of a dermoid cyst.

Both epidermoid and dermoid cysts may be congenital or acquired. Congenital lesions are thought to arise from the sequestration of ectoderm or endoderm within the deeper tissues along embryologic “folds.” In this respect they are similar to branchial cleft cysts, although they typically do not have sinus tracts nor do they arise from deep structures in the neck. Acquired cysts are commonly termed inclusion cysts because they are believed to result from traumatic implantation of a portion of the skin into the underlying layers, which can result in the ectopic formation of a dermal cyst lined with squamous epithelium in any associated location. Depending on the size and depth of these lesions, preoperative imaging with ultrasonography, computed tomography (CT) or magnetic resonance imaging (MRI) may be indicated for diagnosis and surgical planning ( Fig. 13 ). The majority are amenable to direct surgical excision, and every effort should be made to remove the cysts without rupture of the cyst and spillage of contents. Epidermoid excision should include the overlying skin, whereas dermoids are often attached to the underlying periosteum and require removal of the involved segment of periosteal attachment.

Axial ( A ) and coronal ( B ) images of a large dermoid cyst.
Fig. 13
Axial (
A ) and coronal (
B ) images of a large dermoid cyst.

Teratomas of the head and neck are rare tumors that are composed of all 3 embryologic layers: ectoderm, mesoderm, and endoderm. These tumors may include any type or combination of tissues normally found within the human body. Although they are benign, they tend to grow more rapidly than other dermoid cysts. In addition, their location is less predictable, and proximity to vital structures can make surgical excision difficult. Preoperative imaging with CT or MRI is normally indicated for diagnosis and surgical planning. Teratomas can present as an epignathus that may impinge on the airway. In the developed world, these are normally diagnosed prenatally with ultrasonography. If peripartum respiratory compromise is feared, the obstetric plan should include options for airway control including intubation or tracheotomy. An Ex Utero Intrapartum Therapy (EXIT) procedure may be indicated depending on the size and location of the mass, and should be considered and coordinated in advance of delivery.


Lymphatic Malformations

Lymphatic malformations, previously termed lymphangiomas or cystic hygromas, are presently classified as vascular malformations, and occur in 1 out of every 2000 to 4000 births. These malformations are more commonly found as isolated lymphatic lesions that tend to be of low flow in character, but can be seen in combination with arterial or venous vasculature as mixed lymphovascular lesions. Lymphatic malformations are thought to arise as a benign growth of the lymphatic system; however, they can have significant local impact because of their growth potential and infiltrative nature.

Embryologically the lymphatic system develops from vascular endothelial cells. The system is composed of thin-walled channels with limited basement membrane structure, allowing for increased permeability. The lymphatic system acts to drain extravascular fluid, direct antigens to regional lymph nodes, and absorb ingested fat.

Lymphatic malformations are most commonly seen in the neck, but can be found anywhere in the soft tissues of the face and oral cavity; they are classically noted as a soft and compressible cystic mass that can be transilluminated. Lymphatic malformations can range in size and severity from small isolated lesions to extensive cervicofacial lesions ( Fig. 14 ). The malformations may cause both cosmetic and functional disturbances, including airway compromise and long-term distortion of facial growth. Although smaller lesions have been reported to regress without intervention, all of such lesions have the potential for rapid expansion secondary to hemorrhage, trauma, or infection.

An infant with a large cervical-facial lymphatic malformation of the left anterior neck. ( A ) Lateral view showing extent of lesion from a cephalad-caudal perspective. ( B ) Inferior view of large lymphatic malformation with mild external airway impingement.
Fig. 14
An infant with a large cervical-facial lymphatic malformation of the left anterior neck. (
A ) Lateral view showing extent of lesion from a cephalad-caudal perspective. (
B ) Inferior view of large lymphatic malformation with mild external airway impingement.

Clinical diagnosis is confirmed with CT and/or MRI for complete characterization ( Fig. 15 ). This imaging includes identification of microcystic and macrocystic components as well as delineation of anatomic location and extent of disease in relation to the surrounding vital structures. The mainstay of treatment is surgical resection or debulking. Timing is debatable, and depends on the extent and impact of the lesion. Complete excision may be difficult without sacrifice of vital structures, and often multiple debulking procedures are performed. Multiple protocols regarding timing of surgical intervention and potential reconstruction are reported in the literature. Nevertheless, patients must be monitored for recurrence and long-term growth disturbances.

( A ) Axial CT image of a large lymphatic malformation. ( B ) Coronal magnetic resonance image of a large lymphatic malformation.
Fig. 15
(
A ) Axial CT image of a large lymphatic malformation. (
B ) Coronal magnetic resonance image of a large lymphatic malformation.

Sclerotherapy has been increasingly studied and used as a viable option to surgical resection, particularly in macrocystic lesions. Multiple protocols and sclerosant agents are currently being evaluated, including OK-432 (Picinabil), bleomycin, alcohol, and hypertonic saline. Consideration must be given to the technique and control of infiltration as well as potential postoperative edema and pain.

For more in-depth discussion of lymphatic malformations, the reader is referred to the article on vascular malformations by Abramowicz and Padwa elsewhere in this issue.


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