Structural Anomalies of the Gastrointestinal Tract

Mouth

Newborns commonly have transient inclusion cysts in the mouth that may be classified into three types: Epstein pearls, Bohn nodules, and dental lamina cysts. Epstein pearls are small keratin-filled nodules found in the midline of the palate. They are thought to be epithelial inclusion cysts located at the developmental fusion line of the palate. Bohn nodules are firm white or gray nodules, usually found along the alveolar (dental) ridges and are remnants of developing salivary glands. Dental lamina cysts are small, raised, white papules in the midline of the palate or on the alveolar (dental) ridges. Although at times concerning in appearance, all three types of oral inclusion cysts are benign and usually asymptomatic. Their natural history is to spontaneously rupture and fuse with the oral epithelium within 5 months of birth, thus conservative management is appropriate and treatment is rarely necessary. Oral inclusion cysts may sometimes be confused with an oral cavity tumor such as a small congenital epulis or with the eruption of a neonatal tooth.

Oral cavity tumors are rare in newborns. The two most common oral cavity tumors are congenital granular cell epulis (CGCE) and oropharyngeal teratoma. CGCE is a benign tumor that presents as a smooth, red or pink mass arising most often from the maxillary alveolar (dental) ridge. CGCE enlarges prenatally but does not usually grow after birth, is not associated with any syndromes, and has an excellent prognosis.

An oral cavity teratoma arises from the upper jaw or palate and is also known as an epignathus. Teratomas are tumors that arise from fetal germ cells during development and consist of cells and tissues derived from all three germ cell layers (ectoderm, mesoderm, and endoderm). In the newborn, they are commonly found in the sacrococcygeal region but may occur in the gonads or other midline, or near-midline, locations. Symptoms are typically caused by compression of normal structures, although malignant degeneration may occur.

Larger oral cavity teratomas may be seen on prenatal imaging, but granular cell tumors are typically smaller and discovered on physical examination after birth. Granular cell tumors and oral cavity teratomas vary in size and, when large, their mass effect may cause feeding difficulty and even upper airway obstruction. Most oral cavity tumors require surgical resection. The timing of surgery depends upon the severity or potential severity of the symptoms.

Tongue

The tongue is critical for sucking and swallowing, so congenital disorders such as aglossia, ankyloglossia, and macroglossia are usually noted early in life. Aglossia, or congenital absence of part or all the tongue, is a very rare condition caused by failure of tongue embryogenesis in weeks 4 to 8 of gestation. It is usually associated with craniofacial and limb anomalies.

Ankyloglossia is commonly known as “tongue-tie.” Several classification schemes exist for ankyloglossia, including the Corylios classification which describes four subtypes based on the location of attachment. By far the most common form of tongue-tie is ankyloglossia inferior, which is an abnormally short, thickened, and/or tight inferior frenulum. Ankyloglossia can also be described as anterior or posterior. Anterior ankyloglossia refers to a lingual frenulum that extends to the tip of the tongue or near the tip of the tongue that restricts tongue mobility.

There is significant debate about the degree to which ankyloglossia interferes with tongue movement, feeding, and speech with some classification systems incorporating function in addition to anatomy, that is, Hazelbaker Assessment Tool for Lingual Frenulum Function and the Bristol Tongue Assessment Tool. Overall, most newborns with ankyloglossia have no difficulty breastfeeding; however, if they do have difficulties then lactation evaluation and counseling are the next steps. If feeding difficulties persist, then frenotomy (the surgical division of the frenulum) may improve feeding. While ankyloglossia inferior may impact the articulation of speech, it does not usually delay overall speech and language development. Ankyloglossia superior is a rare but more serious anomaly that refers to a fibrous or osseous connection between the tongue and the hard palate. Ankyloglossia superior is associated with other significant anomalies, such as cleft palate, microglossia, micrognathia, GI malformations, and deformed limbs. Ankyloglossia superior can cause difficulty in feeding and even airway obstruction, making early recognition and treatment necessary.

Macroglossia means enlargement of the tongue and is defined as tongue protrusion beyond the teeth or alveolar ridge during resting posture. Macroglossia is seen in 4.63/100,000 live births, with about half being isolated and half syndromic. Macroglossia is more common among female infants and African Americans. Macroglossia may be classified as “true macroglossia” or “pseudomacroglossia.” True macroglossia can be due to muscle hypertrophy of the tongue, which is usually the result of a genetic abnormality, such as Beckwith–Weidemann syndrome. Tissue infiltration from amyloidosis, infection, hemangiomas/lymphangiomas, or systemic diseases such as hypothyroidism and diabetes can also lead to macroglossia. Pseudomacroglossia occurs when the tongue appears large because of a relatively small oral cavity such as in babies with mandibular hypoplasia (micrognathia) or when the tongue is displaced anteriorly. Surgical treatment is needed if there is airway compromise, dysphagia, or dysarthria. Operations for macroglossia aim to reduce the size of the tongue and preserve its function.

Salivary Glands

The salivary glands (the parotid, submandibular, and sublingual glands) may be the source of several newborn problems. A ranula is a mucus-filled cyst arising from the sublingual gland. In newborns, a ranula is caused by congenital obstruction of a sublingual gland duct. Ranulas that are entirely intraoral are known as simple ranulas, while those that extend through the floor of the mouth beyond the mylohyoid muscle are known as “plunging” ranulas and present as a submandibular or neck mass. A ranula may be suspected on physical examination, and diagnosis can be confirmed by ultrasound, computed tomography (CT), or magnetic resonance imaging (MRI). If physical examination and imaging are not definitive then aspiration of the cyst showing yellow fluid containing amylase and mucin confirms the diagnosis. Ranulas may spontaneously resolve and thus may be observed for up to 6 months before excision or sclerotherapy.

Neonatal suppurative sialadenitis and parotitis are rare infections of the salivary and parotid glands, respectively, but should be considered in any newborns presenting with unilateral inflammatory submandibular or parotid swelling. Bacterial contamination of the glands is from the oral cavity via the draining ducts or from hematologic spread from transient bacteremia. Risk factors for these infections include prematurity, prolonged nasogastric feeding, mechanical ventilation, dehydration, and maternal mastitis. Staphylococcus aureus is the most common causative organism, though Streptococcus species , Escherichia coli , and Haemophilus influenzae have also been reported. Treatment with broad-spectrum intravenous antibiotics is recommended, including an anti-staphylococcal β-lactam and an aminoglycoside or third-generation cephalosporin. Although rare, an abscess can form, causing airway compromise and warranting urgent surgical drainage.

Parotid hemangiomas are the most common salivary gland tumors in newborns. They present as a rapidly growing mass in the preauricular area. They may be segmental, involving structures in the distribution of the V3 (mandibular) branch of the trigeminal nerve, including the parotid gland, the overlying skin, and the airway. Alternatively, they may be focal, located within and involving only the parotid gland. Hemangiomas traditionally have a rapid growth phase in the first months of life followed by spontaneous involution over the next decade. Diagnosis is by physical examination and is confirmed by imaging with Doppler ultrasound and sometimes MRI. Observation alone is appropriate for small, non-disfiguring lesions with no systemic manifestations such as congestive heart failure. Treatment options include intralesional corticosteroids, systemic nonselective β-blocker (i.e., propranolol), endovascular sclerotherapy, and surgical resection with intraoperative facial nerve mapping.

Branchial Anomalies

During early development, the flat, trilaminar embryonic disc forms into a cylindrical body, and in the head, neck, and upper chest this process involves the pharyngeal or branchial (Greek for gills ) apparatus. (Branchial is the term most used in clinical medicine to describe these developmental structures, so we will use it here.) The branchial apparatus consists of a series of arches that fold and meet in what will be the ventral midline. The arches contain mesoderm and are separated by indentations that on the outer ectodermal surface are called clefts and on the inner endodermal surface are called pouches. The arches and separating clefts and pouches are numbered based on their cranial to caudal embryonic positioning ( Fig. 61.1 ).

Branchial cleft anomalies arise from incomplete obliteration of the embryonic clefts and pouches and result in an epithelial-lined cyst, sinus, or fistula. A cyst has no direct connection from its epithelial inner lining to the normal epithelium of the skin or pharynx. In contrast, a sinus is an abnormal epithelial extension from either the skin or pharynx, and a fistula is an abnormal epithelial connection between skin and pharynx. Most branchial cleft anomalies are cysts, and 95% of the cysts arise from the second branchial cleft. Although they are congenital anomalies present since birth, they often present in older children and adolescents or even adults. They usually present as neck masses on the anterior border of the sternocleidomastoid muscle. These neck masses may be asymptomatic, or they may produce symptoms because of mass effect or infection. Diagnosis of the cyst is made by the characteristic position on physical examination and may be supported by ultrasound, CT, or MRI appearance. A true fistula may be demonstrated by contrast esophagram. Treatment of branchial cleft cysts includes initial treatment of any complicating infection and then complete surgical excision when the infection has resolved. Surgical excision is well tolerated with minimal morbidity.

Thyroid

The thyroid may be the source of a neck mass when remnants of its embryologic origin persist and enlarge, when the gland is in an abnormal location, or when it is enlarged in the normal location. During weeks 5 to 7 of gestation the rudimentary thyroid migrates from the foramen cecum (i.e., the base of the tongue) to its final position in the lower neck anterior to the trachea. At the onset of normal migration, the endoderm of the primitive pharynx invaginates and forms the thyroglossal duct with the developing thyroid gland at its inferior aspect. The duct descends to the lower neck and is usually obliterated by week 10 of gestation. Incomplete obliteration of the duct may lead to a thyroglossal duct cyst that presents as a midline neck mass between the hyoid bone and the thyroid gland. Thyroglossal duct cysts have a propensity to become infected, and surgical excision is indicated.

Simple excision of a thyroglossal duct cyst results in a high rate of recurrence, presumably because of small residual bits of thyroglossal duct tissue not in continuity with the main cyst. Therefore, the operation of choice is the Sistrunk procedure: an en bloc excision of the cyst and its tract, including the middle part of the hyoid bone. Previous infections increase the risk for cyst recurrence after surgery. While rare, when identified later in life, thyroglossal duct cyst carcinoma is reported, with a mean age at diagnosis of 39.5 years.

Disordered thyroid development may result in abnormally located or ectopic thyroid. In general, functional thyroid tissue not located anterior to the second, third, or fourth tracheal rings is considered to be ectopic. Ectopic thyroid tissue can be found anywhere between the foramen cecum and the mediastinum. The most common location for ectopic thyroid is the tongue. Lingual thyroid results from the failure of normal migration of the thyroid during development and presents as a mass in the posterior midline of the tongue. Most patients with a lingual thyroid do not have additional thyroid tissue in the normal position. A large lingual thyroid may cause symptoms of airway obstruction.

A diffusely enlarged, nontender thyroid gland at birth is known as a congenital goiter. It may be associated with hyperthyroidism, hypothyroidism, or a euthyroid state. The diagnosis of congenital goiter can be confirmed with ultrasound. Thyroid function should be assessed to determine the need for thyroid hormone replacement.

Other Neck Masses

Neck masses are often distinguished by their location. As noted, the branchial anomalies usually present as lateral neck masses. The differential for lateral neck masses presenting in the first few weeks of life also includes cystic hygromas and those associated with torticollis.

The “sternocleidomastoid pseudotumor of infancy,” or the neck mass associated with congenital muscular torticollis, is a firm, nontender thickening in the lower half of the sternocleidomastoid muscle. The mass is associated with tightness and shortening of the sternocleidomastoid muscle that leads to a characteristic positioning of the patient's head—the face turned away from the side of the lesion with the chin tilted up. The range of motion is reduced. The etiology is unknown, but it is associated with difficult deliveries. The condition is more common in males, more frequent on the right, and generally presents in the first few weeks of life. Diagnosis is by characteristic examination findings. Treatment is directed at improving the range of motion and posture through physical therapy. Surgery is not usually required.

Cystic hygromas are congenital lymphatic malformations. Lymphatic malformations may be defined by the size of the cystic spaces (<2 cm is microcystic, >2 cm is macrocystic), and location is based on the de Serres staging system or the Mulliken/McGill system. Cystic hygromas in the neck are classically macrocystic and located in the posterior triangle, more commonly on the left side. They are present at birth and typically grow with the child but may enlarge suddenly with internal hemorrhage or infection. Treatment is by surgical excision or sclerotherapy. A systematic review in 2012 did not find conclusive evidence to support the superiority of one treatment modality over the other.

In addition to thyroid anomalies, midline neck masses in newborns include dermoid cysts, teratomas, and, rarely, an undescended thymus. Dermoid cysts are subcutaneous cysts lined by keratinized, stratified, squamous epithelium with appendages such as hair follicles, sweat glands, and sebaceous glands. They commonly occur on the face and scalp at lines of embryonic fusion and can also occur in the midline neck near the hyoid bone and be confused with thyroglossal duct cysts. Dermoid cysts are prone to infection and should be excised. Midline dermoid cysts or those over skull suture lines may connect to the dura, and imaging should be considered in these cases prior to excision. Imaging is not needed in most other cases. Teratomas in the neck are often found in the midline and are biologically the same tumor as oropharyngeal teratomas, described in the earlier section. They usually originate near the larynx and trachea and may cause airway obstruction. Almost all midline neck masses require surgical resection.

Esophageal Atresia

Esophageal atresia is the most common congenital anomaly of the esophagus and occurs when the esophagus is congenitally separated into segments that are not in continuity. Esophageal atresia is often associated with a tracheoesophageal fistula (TEF).