50 Congenital Malformations of the Head & Neck Flashcards
What is the differential for a congenital neck mass?
What is the differential for a congenital neck mass?
See Table 50-1.
What is a thyroglossal duct cyst (TDC) and how does it form?
What is a thyroglossal duct cyst (TDC) and how does it form?
TDCs are the most common congenital neck mass in the pediatric population. At 3 weeks of gestation, the thyroid gland forms from a diverticulum at the oral tongue (the foramen cecum). As development continues this diverticulum descends to fuse with components of the fourth and fifth branchial pouch, anterior to or through the hyoid, and to the thyroid’s final location in the neck. At 5 to 8 weeks, the tract formed by this descent obliterates leaving the foramen cecum proximally and the pyramidal lobe of the thyroid distally. Incomplete obliteration results in a TDC anywhere along this tract. Because of its origin, a TDC generally elevates with extrusion of the tongue.
What must be considered before surgical treatment and what is the treatment of choice?
What must be considered before surgical treatment and what is the treatment of choice?
Preoperative evaluation for TDC should include preoperative thyroid ultrasound to rule out an ectopic thyroid gland. Failure to do so could mean removing the patient’s only functioning thyroid tissue along with the cyst.
Historically, recurrence of a TDC was very high (38% to 70%). The Sistrunk procedure includes excision of the cyst, the tract connecting it to the foramen cecum, and the central portion of the hyoid bone resulting in a recurrence rate of 2.6% to 5%. It is also notable that rarely (less than 1%), TDCs can harbor malignancy. This is usually well differentiated thyroid carcinoma. Complete removal with Sistrunk offers an excellent cure rate.
Two additional midline masses are teratomas and dermoid cysts. How do these differ?
Two additional midline masses are teratomas and dermoid cysts. How do these differ?
Teratomas are composed of all three germ layers and are larger and typically more symptomatic than dermoid cysts. They are often diagnosed by prenatal ultrasound and 30% are associated with hydramnios secondary to esophageal obstruction. Dermoid cysts are composed of only ectoderm and mesoderm and form from entrapped epithelium along the lines of embryonic fusion (midline). They will enlarge over time as they fill with sebaceous material and have characteristic “cheesy” contents upon excision.
What are the types of branchial anomalies (BA) and how do they form?
What are the types of branchial anomalies (BA) and how do they form?
An understanding of the embryology is crucial to the identification and management of BAs. At 4 weeks gestation there are 4 pairs of branchial arches and 2 rudimentary arches. These are externally lined with ectoderm and internally lined with endoderm, with mesoderm between. The arches are separated by pouches internally and clefts externally. These clefts and pouches are gradually replaced with mesenchyme forming well-defined anatomic stuctures. When the clefts and pouches persist, BAs are formed. There are three types:
- Cyst: remnant with no internal or external opening. Lined with squamous epithelium.
- Sinus: remnant with an external opening, often draining to the skin. Often lined with ciliated columnar epithelium.
- Fistula: remant with internal (aerodigestive tract) and external opening (skin). Also lined with ciliated columnar epithelium.
Discuss the types of BAs in relation to their developmental origin. Where would you expect them to track?
Discuss the types of BAs in relation to their developmental origin. Where would you expect them to track?
BAs follow a predictable course, as each branchial arch has an associated artery, cranial nerve, muscles (innervated by the cranial nerve of that arch), and skeletal/cartilagenous structure. The course of a BA is deep to the structures derived from its own arch and superficial to the structures of the subsequent arches (Table 50-2). First branchial cleft cysts are rare (1% of BA) and present as a cyst, sinus, or fistulae between the external auditory canal and the submandibular area. Type 1 first BAs track lateral to the facial nerve and are duplications of the external auditory canal while Type 2 first BAs are typically medial to the nerve. Both can terminate at the EAC or middle ear. The main differentiation is that Type 1 first BAs do not contain mesoderm while type 2 BAs do. They usually require parotidectomy and facial nerve dissection for excision. Second branchial cleft anomalies are most common (95%) and are found along the anterior border of the SCM. They track between the internal and external carotid arteries and terminate at the tonsillar fossa. Third and fourth branchial anomalies are rare and present lower along the anterior border of the SCM and terminate in the ipsilateral piriform sinus. Because of the embryology, the tract of a fourth BA on the right loops under the subclavian, while on the left will travel to the mediastinum and under the aortic arch before leading to the piriform.
What is a pseudotumor of infancy?
What is a pseudotumor of infancy?
This refers to a firm rounded mass within the sternocleidomastoid (SCM) muscle. Also called SCM tumor of infancy or fibromatosis coli, it presents usually 2 to 3 weeks after birth. The mass is characterized histologically by dense fibrous tissue and the absence of striated muscle. Implicated in the etiology is birth trauma, ischemia of muscle, or intrauterine positioning. Conservative treatment and physical therapy results in resolution by 1 year of age in greater than 80% of cases.
What is the differential for a midline nasal mass?
What is the differential for a midline nasal mass?
- Nasal dermoid: Most common of the three. Nasal dermoids present as a noncompressible mass over the nasal dorsum, anywhere from the glabella to the columella. There is usually an assocated midline pit with hair at the opening. Treatment is surgical excision.
- Glioma: Likely forms when a cranial suture closes, isolating a portion of brain tissue from the cranial cavity. They can sometimes have a fibrous stalk that maintains a connection to the CNS but by definition they do not contain herniated dura.
- Encephalocele: A herniation of meninges and brain matter through a bony skull base defect. The mass will illuminate and will enlarge with straining or crying (Furstenberg’s sign). All midline masses should be imaged prior to operative planning (MRI and CT may be complementary).
What is choanal atresia (CA)?
What is choanal atresia (CA)?
At 1 in 8000 live births, CA is the most common congenital nasal anomaly. It is more commonly unilateral, right-sided, and affects females more than males. The choana is the posterior nasal aperture by which air flows from the nasal cavity into the nasopharynx. It can be bony or membranous with most recent data citing membranous as more common. Because infants are obligate nasal breathers, bilateral CA (usually associated with a syndrome or association such as CHARGE, Crouzon, or Treacher-Collins) is life-threatening. Atresia is suspected when a 5–6 French catheter cannot be passed into the nasopharynx at birth.
What is the most common cause of stridor in infants?
What are the classic findings on exam?
What is the most common cause of stridor in infants? What are the classic findings on exam?
Laryngomalacia accounts for 60% to 75% of all congenital laryngeal anomalies. The associated stridor is caused by the airflow dynamics of the supraglottic tissues (epiglottis, aryepiglottic folds, arytenoids) upon inspiration. Typically infants have few to no symptoms at birth but gradually develop high-pitched inspiratory stridor in the first weeks of life that usually resolves by 1 year of age. In cases where laryngomalacia causes significant breathing or feeding problems it is treated with supraglottoplasty. Because of its dynamic nature, laryngomalacia must be diagnosed with endoscopic visualization while the infant is awake and breathing. An omega-shaped epiglottis and foreshortened aryepiglottic folds are the classic finding. Laryngomalacia is usually associated with significant laryngoesophageal reflux making acid supression first line in nonsurgical therapy.
How common is congenital vocal fold immobility?
How common is congenital vocal fold immobility?
Congenital immobility of one or both vocal cords is the second most common congenital laryngeal disorder. Unilateral immobility may manifest as a weak or breathy cry, poor feeding, or aspiration. Bilateral immobility, while thankfully less common, can be life-threatening and results in biphasic stridor at birth. Etiology is often idiopathic but can include birth trauma, hydrocephalus, spina bifida, cerebral palsy, and Arnold-Chiari malformation.
What are the two most common malformations of the subglottis?
What are the two most common malformations of the subglottis?
Congenital subglottic stenosis (SGS) is defined as a diameter of <4 mm in the newborn (3 in the premature infant) and can be considered congenital only prior to any attempt at intubation. The stenosis can be membranous (more common, less severe) or cartilagenous. SGS will typically present in the first few months of life with biphasic or inspiratory stridor and recurrent/persistent croup. Depending on the severity of stenosis, treatment can include watchful waiting with medical management of episodic croup, anterior cricoid split, or tracheostomy.
A hemangioma of the subglottic area classically presents in the third or fourth week of life with inspiratory or biphasic stridor, harsh cough, abnormal cry, and failure to thrive. Approximately 50% of infants with subglottic hemangioma have additional cutaneous hemangiomas. Spontaneous regression of these lesions often occurs by 5 years of age. When the lesion is obstructing the airway, treatment options include beta blockers, cryotherapy, sclerotherapy, systemic or intralesional steroid, open surgical resection, tracheostomy, and laser ablation.
What is a laryngotracheal cleft?
What is a laryngotracheal cleft?
Laryngeal and laryngotracheal clefts are uncommon posterior clefts of varying severity caused by incomplete development of the tracheoesophageal septum. Presentation includes a hoarse cry, cyanosis, coughing, choking, stridor, aspiration, and recurrent pneumonia depending on the length of the cleft.
They are classified into 4 types based on the distal extent of the cleft:
- Type 1 is an interarytenoid cleft with absence of the interarytenoid muscle (above the level of the vocal cords)
- Type 2 extends into the upper cricoid
- Type 3 involves the entire cricoid with or without extension into the cervical trachea
- Type 4 cleft extends into the thoracic trachea
Name the five types of tracheoesophageal anomalies and discuss their presentation and diagnosis.
Name the five types of tracheoesophageal anomalies and discuss their presentation and diagnosis.
- Esophageal atresia with distal tracheoesophageal fistula (≈85%)
- Isolated esophageal atresia without fistula (≈8%)
- Tracheoesophageal fistula without atresia or H-type (≈5%)
- Esophageal atresia with proximal tracheoesophageal fistula (≈1%)
- Esophageal atresia with proximal and distal tracheoesophageal fistula (≈0.5% to 1%)
When atresia is present, there are copius oral secretions with episodes of coughing and respiratory distress with feeds in the first few days of life. Symptoms depend on the severity of atresia. A nasogastric tube cannot be passed. The H-type fistula can present later with chronic feeding difficulties and recurrent respiratory distress and/or pneumonia. Diagnosis can be made with a barium esophagram and/or endoscopy.
What are the two classifications of tracheal malformations? What causes them?
What are the two classifications of tracheal malformations? What causes them?
Intrinsic malformations are caused by improper development of the trachea. Examples of intrinsic malformations include tracheal agenesis (not compatible with life), congenital tracheal stenosis (often with complete tracheal rings), and tracheomalacia.
Extrinsic causes of tracheomalacia are secondary to compression of the airway from the structures that surround it. Causes include vascular compression (e.g., innominate artery, double aortic arch, right aortic arch with persistent ductus or ligamentum arteriosum), masses in the neck and mediastinum, and thyromegaly.
