Congenital neck masses

Congenital neck masses are developmental anomalies that are most often caused by an incomplete obliteration of embryonic structures (e.g., thyroglossal duct cyst, branchial cleft cyst). Other causes include congenital tumors (especially dermoid cysts), macrocystic lymphatic malformation of the neck, and congenital goiter. Congenital neck masses typically manifest in childhood. Location of the mass depends on the tissue of origin (e.g., midline for thyroglossal duct cysts; lateral for branchial cleft cysts). Larger masses may cause compression of the trachea and esophagus. Fever, pain, and rapid increase in the size of the mass indicate infection. Diagnosis involves clinical examination and imaging; ultrasound neck is the preferred initial imaging modality. Surgical excision is the definitive management; incomplete excision is associated with an increased risk of recurrence. Definitive diagnosis of the type of mass is established on histopathology of the excised mass. Specialist referral is recommended for congenital neck masses detected on prenatal ultrasound for management of high-risk pregnancy and delivery planning.

Congenital neck masses can be broadly categorized by their anatomical location and include: ^[1][2][3][4]

• Midline lesions
  • Thyroglossal duct cyst (most common)
  • Dermoid cyst and epidermal inclusion cyst
  • Plunging ranula ^[5]
  • Congenital tumors ^[2][6]
  • Congenital goiter
  • Bronchogenic cyst (rare) ^[5]
• Lateral lesions
  • Branchial cleft cyst
  • Lymphatic malformation (e.g., macrocystic lymphatic malformation of the neck)
  • Vascular malformation or tumor (e.g., infantile hemangioma)
  • Epidermoid cyst
  • Neuroblastoma
  • Thymic cyst (often left-sided)
  • Fibromatosis colli (sternomastoid tumor of infancy)

The most common congenital neck masses in order of incidence are thyroglossal duct cysts, branchial cleft cysts, and dermoid cysts. ^[7]

Focused history ^[4]

• Features of neck mass
  • Present at birth or later onset
  • Changes in size
• Signs of infection
  • Fever, pain, erythema, and/or tenderness
  • Rapid increase in size
  • Preceding or concurrent respiratory infection
• Signs of compression of trachea and/or esophagus (e.g., stridor, dysphagia) ^[2]
• Features suggesting an alternative diagnosis; e.g., see:
  • Differential diagnoses of congenital neck masses
  • Red flags of cervical lymphadenopathy in children

Neck masses present at birth are usually benign. ^[4]

Focused examination ^[4]

• Location
• Size
• Palpation (e.g., consistency, mobility)
• Movement with swallowing or tongue protrusion (for midline masses)
• Associated sinus or fistula
• Features of inflammation (e.g., erythema, tenderness, localized warmth)

Prenatal management ^[7]

• Fetal neck masses (e.g., macrocystic lymphatic malformation of the neck, cervical teratoma) may be detected on routine prenatal ultrasound.
• Fetal neck mass signals a high-risk pregnancy; refer to specialists (e.g., MFM) for:
  • Prenatal management, including fetal MRI to better delineate the anomalies and facilitate appropriate prenatal counseling and planning
  • Delivery planning, including ex-utero intrapartum treatment if there is risk of airway compromise

Large fetal neck masses can compress the facial structures, trachea, and esophagus, resulting in impaired fetal swallowing, polyhydramnios, and airway obstruction. ^[7]

Postnatal management ^[4][7]

Diagnostics

Diagnosis is usually based on clinical examination and imaging. Histopathology of the excised mass is often required for definitive diagnosis.

• Imaging ^[8][9]
  • Ultrasound neck: initial modality of choice for congenital neck mass
  • MRI neck or CT neck : for deep masses, to evaluate for malignancy, and/or for surgical planning
• Additional diagnostics
  • CBC with differential: Consider if malignancy or infection is suspected. ^[4]
  • Additional diagnostic studies; (e.g., FNAC, biopsy) may be considered in cases of diagnostic uncertainty. ^[4][5]

Treatment ^[4][7]

• Surgical excision is the definitive management of most congenital neck masses.
• Refer all patients to a specialist (e.g., head and neck, OMFS) for surgery.
• Antibiotics (with or without drainage) are indicated before excision of infected masses; see "Empiric antibiotic therapy for nonpurulent and purulent SSTIs."

• Any location ^[4][10]
  • Cervical lymphadenopathy (benign or malignant)
  • Malignancies (e.g., cervical teratoma, soft tissue sarcomas, metastatic nasopharyngeal carcinoma)
  • Benign soft tissue tumor (e.g., pilomatrixomas, lipomas, hemangiomas, fibromas, neurofibromas)
  • Arteriovenous fistula
• Midline ^[4][10]
  • Goiter
  • Thyroid cancer
• Lateral ^[4][10]
  • Tumors of the salivary gland
  • Parotitis
  • Chronic sialadenitis
  • Carotid body tumors

A thyroglossal duct cyst is a congenital anomaly that arises from a remnant of the thyroglossal duct. ^[5]

Epidemiology ^[2][5]

• Incidence: ∼ 7% of the population ^[5]
• Accounts for 70% of congenital neck masses in children ^[2]
• Second most common neck mass overall in children (after cervical lymphadenopathy) ^[5]
• Can manifest any time between infancy and young adulthood

Pathophysiology ^[5][7]

• The thyroid gland originates from the foramen cecum at the base of the tongue and descends caudally into the neck, forming the thyroglossal duct.
• The thyroglossal duct is a temporary structure that is normally obliterated around gestational weeks 8–10.
• If the thyroglossal duct is not obliterated, midline neck cysts or ectopic thyroid tissue can develop anywhere along its path.

Clinical features ^[2][4][5]

• Typical manifests as a painless, well-circumscribed midline neck mass
• Can occur anywhere along the thyroglossal duct tract; usually located at or above the hyoid bone
• Elevates with swallowing and tongue protrusion
• Inflamed cysts (e.g., due to infection, trauma) may be associated with dysphagia, neck pain, and/or throat pain. ^[11]

Thyroglossal duct cyst can manifest for the first time in adulthood as an infected cyst or, rarely, as a thyroglossal duct carcinoma. ^[1]

Diagnostics

Diagnosis is based on clinical evaluation and imaging. Definitive diagnosis is established on histopathology. ^[2][7]

• Ultrasound neck with color Doppler ^[5][7][9]
  • Preferred initial imaging modality
  • An uncomplicated cyst appears as a well-defined hypoechoic or anechoic midline or para-midline thin-walled cyst.
  • Features of an infected cyst include peripheral vascularity, internal debris, and thickened rim.
• Thyroid function tests: typically normal ^[12]
• FNAC: rarely performed; indicated in case of diagnostic uncertainty or suspected malignancy ^[13]
• Histopathology (of excisional biopsy) ^[13]
  • Cyst lined with squamous and/or pseudostratified ciliated or cuboidal epithelium
  • Thyroid follicles are often present in the cyst wall.

Treatment

Refer patients to a specialist (e.g., head and neck surgery, OMFS) for management, including:

• Surgery (Sistrunk procedure) ^[2][7]
  • Indicated in all patients as a definitive treatment to prevent recurrence and complications (e.g., infection, malignancy)
  • Involves removal of the entire thyroglossal duct, a portion of the hyoid bone, and the cyst
  • The location of the thyroid gland should be verified preoperatively. ^[2][5]
    • Ultrasound neck is preferred.
    • Additional imaging (e.g., CT neck, MRI neck, thyroid scintigraphy) may be indicated for suspected ectopic thyroid tissue. ^[14]
• Antibiotics (with or without aspiration) ^[2][15]
  • Administered before definitive surgery for infected thyroglossal duct cysts
  • See "Empiric antibiotic therapy for nonpurulent and purulent SSTIs" for guidance.

Thyroglossal duct cysts are typically benign. < 1% develop malignancy, often in adulthood. ^[2]

A branchial cleft cyst is a congenital fluid-filled neck mass that develops due to incomplete obliteration of the branchial apparatus during embryonic development. ^[5][16]

Epidemiology ^[5]

• Second most common congenital neck mass in children, accounting for ∼ 20% of cases ^[2][5]
• Age at presentation: most common in childhood and young adulthood ^[5][17]

Pathophysiology ^[1]

• The mass arises from incomplete obliteration of the branchial apparatus during embryogenesis.
• Most (75–95%) arise from the second branchial cleft or cervical sinus. ^[1][2]

Clinical features ^[1][7][16]

Features of the second branchial cleft cyst are detailed here. Other branchial cleft lesions are rare and are not detailed in this article.

• Usually nontender, fluctuant, mobile neck mass
• Typically located lateral to the midline, anterior to the sternocleidomastoid muscle
• The mass does not move with swallowing or tongue protrusion.
• Infected cysts can manifest as a rapidly enlarging mass and cause dysphagia and/or airway compression.
• A concurrent draining fistula or pit may be present.
• May be associated with branchio-oto-renal syndrome (more common with bilateral cysts) ^[7][9]

Branchial cleft cysts are the most common branchial cleft anomaly. Sinuses and fistulae may also occur. ^[2][16]

Diagnostics ^[9][16]

Diagnosis is based on clinical evaluation and imaging. Definitive diagnosis is established on histopathology.

• Imaging
  • Ultrasound neck: preferred initial imaging modality to evaluate cystic masses of the neck
    • An uncomplicated cyst is thin-walled, well-defined, anechoic, and compressible.
    • Typically located posterior to the submandibular gland, anterior to the sternocleidomastoid, and lateral to the carotid sheath
    • Characteristically extends between the internal and external carotid arteries above the carotid bifurcation
  • Fistulogram: indicated to evaluate the course of a fistula
• FNAC: indicated in case of diagnostic uncertainty (e.g., to rule out malignancy in adults with a cystic neck mass)
• Histopathology (of tissue from excisional biopsy): benign cyst lined by stratified squamous or ciliated columnar epithelium

Treatment ^[7][16]

Refer patients to a specialist (e.g., head and neck surgery, OMFS) for management, which includes:

• Surgery
  • Indicated in all patients as a definitive treatment to prevent recurrence and complications (e.g., infection, malignancy)
  • Involves complete surgical excision of the cyst and any associated fistula or sinus tract
  • Minimum age for excision is not well established.
  • Incomplete resection is associated with a risk of recurrence. ^[7]
• Antibiotics (with or without aspiration)
  • Administer before definitive surgery for infected cysts.
  • See "Empiric antibiotic therapy for nonpurulent and purulent SSTIs" for guidance.

Macrocystic lymphatic malformation (previously called "cystic hygroma") is a congenital low-flow malformation of the lymphatic channels that results in a neck mass mostly composed of cysts ≥ 2 cm. ^[2][5][18]

Epidemiology

• Overall incidence of all lymphatic malformations: 1 in 2000–16,000 births ^[18]
• Approximately 75% of lymphatic malformations occur in the head and neck. ^[18]
• Posterior cervical lesions are associated with aneuploidy; (e.g., Turner syndrome, trisomy 21, trisomy 13, trisomy 18), cardiac malformations, and perinatal mortality. ^[2]

Clinical features ^[5][18]

• May be detected in utero on routine prenatal ultrasound
• Clinically apparent at birth or by 2 years of age as a soft or firm compressible painless mass
  • Most commonly located in the posterior triangle of the neck
  • May increase in size with age and/or after an upper respiratory tract infection
  • Positive transillumination test ^[19][20]
• Large masses may cause airway compromise.
• Infected lesions manifest with fever, localized pain, overlying erythema, and rapid enlargement.
• Other complications include intralesional hemorrhage, spontaneous thrombosis, functional impediment, and cosmetic disfigurement.

Diagnostics

Diagnosis may be made on prenatal ultrasound or postnatally, based on clinical findings and imaging. ^[18]

• Findings on routine prenatal ultrasound ^[21]
  • Lucency of the posterior neck tissue with nuchal thickening
  • OR lucency of the anterior or ventral neck
• Findings on postnatal ultrasound neck with color Doppler (preferred) ^[5][18]
  • Anechoic or hypoechoic thin-walled cysts with septations
  • Cysts are typically ≥ 2 cm (i.e., macrocysts), with or without some microcysts (< 2 cm)
  • No flow on Doppler

Management

Prenatal management ^[21]

Management is typically performed by a specialist (e.g., OMFS, MFM) and may include:

• Genetic counseling
• Chromosome analysis (e.g., noninvasive prenatal testing, amniocentesis)
• Surveillance imaging for associated anomalies
• See "Management of high-risk pregnancies" for details.

Postnatal management ^[18]

Management depends on the size, location, associated complications, and patient and/or caregiver preference. Options include:

• Expectant management
  • May be appropriate in infants for small, localized lesions that are not causing any pressure symptoms
  • Some lesions are responsive to compression therapy.
• Pharmacological treatment
  • For acutely enlarged and/or infected cysts
    • Corticosteroids for large lesions causing airway compromise
    • Antibiotics for infected cysts (see "Empiric antibiotic therapy for nonpurulent and purulent SSTIs")
  • To decrease size: mTOR inhibitors (e.g., sirolimus, everolimus)
• Sclerotherapy and laser therapy: minimally invasive interventions for symptomatic lesions
• Surgical excision
  • The only definitive therapeutic option
  • Indications include lesions that are symptomatic, infected, or causing compression of adjacent vital structures.
  • Only partial excision may be feasible depending on the anatomy and size of the lesion.
  • Incomplete excision is associated with an increased risk of recurrence.

Lymphatic malformations typically increase in size with age. Spontaneous resolution is rare. Hence, expectant management is usually appropriate only for small, localized lesions. ^[2][18]