A 4-day-old term female infant is being evaluated for fever, with a rectal temperature of 100.9°F (38.2°C), and an episode of oxygen desaturation to 70% while breathing room air. The mother reports that the infant had increasing fussiness. Prenatal care and delivery were within normal parameters. She denies use of illicit drugs and is unsure of her group B Streptococcus status. The infant has eight to nine wet diapers and about 10 bowel movements per day. She consumes 1 to 2 oz of regular infant formula every 3 hours. The only finding of note on physical examination is the fever. Her neck is supple and has no abnormalities. A full sepsis evaluation is performed, including a complete blood count and blood, urine, and cerebrospinal fluid cultures. Respiratory syncytial virus antigen and influenza test results are negative. Radiographs of the chest and lungs appear normal. The infant is admitted and treatment with ampicillin and cefotaxime is begun. Thirteen hours later, the infant develops respiratory distress manifesting with stridor and desaturation while breathing room air.Physical examination at this time reveals a new cystic, moveable mass on the anterior triangle of her neck. Follow-up radiograph of the neck shows displacement of the trachea to the right. An 80% helium/20% oxygen mixture is started in the pediatric intensive care unit. Computed tomography (CT) scan of the neck and chest shows a 4.0×2.5-cm cystic lesion with an air-fluid level located in the anterior triangle of her neck slightly to the left of midline (Fig. 1). Thyroid study results are normal. Surgical removal of the cyst and histologic evaluation lead to the diagnosis.The patient was taken to the operating room the next day for neck exploration. A cystic mass was exposed, and more than 20 mL of thick, green, foul-smelling, purulent fluid was aspirated from it (Fig. 2). The entire mass was excised surgically without any complications (Fig. 3). Gram stain of the aspirate revealed numerous white blood cells with many gram-positive and gram-negative organisms. Culture grew group B Streptococcus after 24 hours. Pathologic evaluation identified the mass as a thyroglossal duct cyst (TGDC).Congenital cervical anomalies are common otolaryngologic problems encountered during infancy and childhood. Most are due to an abnormality in the sequence of in utero development. (1) Differential diagnoses, in descending order of frequency, include TGDCs, branchial cleft anomalies, dermoid cysts, ranulas, and median cervical clefts. (2) Diagnosis may be difficult in the absence of any visible or palpable midline neck mass. When attempting to confirm the diagnosis, the patient's safety and comfort always should be the first priority. For patients whose histories and physical examination findings are highly suggestive of TGDCs, ultrasonography is the most useful and least invasive tool in defining the consistency of the mass and analyzing the surrounding anatomy. (3) Soft-tissue films of the neck and barium swallow studies are minimally invasive but can be difficult to interpret. CT scan and magnetic resonance imaging provide the best detail of TGDCs in terms of anatomic location, margins, and compression of surrounding structures, but both require a cooperative or sedated patient. Obviously, such requirements may be difficult to achieve in patients who have compromised airways. (4) For suspected lingual cases, direct viewing using nasopharyngeal laryngoscopy should be performed emergently, especially in infants presenting with an unexplained upper airway obstruction.Branchial cleft anomalies are the second most common cause of congenital cervical anomalies. (1) They are seen more laterally and do not move with swallowing. Depending on the arch anomaly, they can be found between the external auditory canal and the anterior border of the sternocleidomastoid muscle. (1) They may present at any age as a painless cyst, sinus, or a fistula with a mucous or purulent drainage. Cases of rapid neck enlargement with respiratory compromise have been reported among neonates. (1) CT scan is the current diagnostic study of choice. The lesions do not resolve spontaneously and, thus, require early and complete surgical excision due to a high incidence of infection. (1)(2)(3)Dermoid cysts, which are lined by epithelium and contain epithelial appendages, represent about 25% of midline anterior neck masses. Other than the anterior portion of the neck, they also can occur in such locations as the occipital or frontal scalp. (2) However, due to lack of mesodermal attachments and connection to the oropharynx, such lesions do not move with deglutition and do not become infected. Ultrasonography and CT scans may help identify epithelial remnants. Fine-needle aspiration is contraindicated due to the possibility of seeding epithelial remnants outside the area of resection. Complete resection is often curative.Ranulas are less common midline cervical cysts caused by blockage of sublingual salivary ducts. They present as cystic swelling in the floor of the mouth, which may lead to significant tongue deviation and affect sucking and swallowing. Although extremely rare, they may grow deep into the fascial planes of the neck. However, compared with TGDCs, they usually are located higher and often are more broad-based. (2) Ultrasonography may be used to define the extent of the lesion. Complete resection is curative.Midline cervical clefts are extremely rare midline neck lesions that may present at birth and may be associated with clefts of the lower lip, tongue, and mandible. They may present as a skin ulcer in the lower portion of the anterior neck associated with a sinus tract, which ends in a blind pouch or may communicate with the sternum or mandible and are much lower. Untreated, they may lead to neck contractures and delayed mandibular or sternal growth. Recurrence risks are extremely high, despite complete surgical excision. (2)TGDCs are well known, oft-encountered lesions in pediatric and otolaryngology practice. Occurring three times more commonly than branchial cleft abnormalities, they account for approximately 40% of all primary neck masses and 70% of congenital neck abnormalities. (1) TGDCs typically involute between 5 and 10 weeks of gestation, but failure of duct obliteration occurs in approximately 7% of the population. (3) Most TGDCs remain asymptomatic and undetected, often until autopsy.Signs and symptoms vary, depending on the location of the cyst. Due to the course of its embryologic development, TGDC remnants can be found from the base of the tongue to the level of the thyroid gland. (1) Most are found in the hyoid region, but some have presented as inferiorly as the suprasternal notch. Most TGDCs are located in the midline, although 10% to 24% are seen laterally, usually to the left. (4) In neonates and infants, respiratory symptoms are the most common reasons for seeking medical attention. Stridor, apnea, dyspnea, respiratory distress, and respiratory failure are possible on presentation. Diaz and colleagues (4) recently published a case involving a 27-day-old infant who presented with apnea, cyanosis, and stridor after extubation. Laryngoscopy revealed compression of the epiglottitis by a round soft-tissue mass, indicated by CT scan as a TGDC between the base of the tongue and hyoid bone. In older children, the most common complaint is a painless cystic midline mass that moves with deglutition or protrusion of the tongue. Secondary infection and cosmetic defects are other reasons for seeking medical attention. Some patients report a foul or bitter taste in their mouths and a decrease in the size of the cyst following compression. Others may develop spontaneous fistulas from trauma or after inadequate surgery. (5)The location of the foramen cecum at the tongue base predisposes TGDCs to secondary infection by oral flora. The most common bacterial perpetrators are Haemophilus influenzae, Staphylococcus aureus, and Streptococcus epidermidis. TGDCs typically are lined by mucus-secreting respiratory epithelium responsible for the mucoid fluid secreted into the cyst. Inflammation of the cyst in response to infection or lymphatic obstruction may initiate metaplastic change of the respiratory epithelium. Several cases of malignant epithelial transformation, usually of well-differentiated types, have been reported. TGDCs can be solitary or multiple and may be associated with functioning or nonfunctioning thyroid tissue. Reports exist of thyroid tissue rests developing numerous forms of thyroid gland pathology, including thyroiditis, hyperthyroidism, and malignancy. (2) As of 2004, 180 cases of malignancy in the solid part of a TGDC have been reported, more commonly in adults but with a few cases reported in children younger than age 6 years. (2) However, because of routine cyst removal, the incidence of malignancy is less than 1%. (2)Frequently, surgical intervention is not indicated initially because many acutely infected TGDCs can be managed with antibiotics and needle aspiration. However, the tendency for open incision and drainage should be avoided because this may rupture the capsule and lead to iatrogenic seeding of contiguous sterile ductal epithelium, thereby increasing the recurrence rate. Surgical therapy is reserved for three separate indications: increasing size of the TGDC, the risk for cyst infection, or the presence of carcinoma. (6) Preoperatively, it is important to differentiate ectopic thyroidal tissue from a suspected TGDC. Ultrasonography and radionucleotide scanning often are helpful adjuncts in confirming the diagnosis. Although only 10% of ectopic thyroid tissue is confined to the neck, it may represent the only thyroid tissue in 75% of affected patients. (6) Unnecessary excision would commit the patient to a lifetime of exogenous thyroid hormone replacement.The standard surgical treatment has remained unchanged since Sistrunk first described his namesake procedure in 1928. The operation involves complete dissection of the cyst, with a cuff of surrounding tissue excised along the entirety of the thyroglossal tract to the level of the foramen cecum. Failure to complete the central hyoid ostectomy translates to a higher recurrence rate due to residual ductal epithelium that frequently is associated intimately with the middle portion of the hyoid bone. In addition, young patient age, skin involvement, previous or concurrent infection, lobulation of the cyst, and rupture of the cyst at operation all predispose to recurrence. (5) Despite employing the most meticulous surgical technique, the Sistrunk procedure is associated with a recurrence rate of 3%. (3)TGDCs are unusual neck lesions in neonates. They often become infected, presenting with signs of inflammation, midline swelling or mass, and external drainage. Most cysts present in preschool-age children and very rarely cause respiratory compromise. The case presented here is very unusual in terms of age at presentation (4 days), the infecting pathogen (group B Streptococcus), location (slightly left of midline), rapid course, and prominent respiratory symptoms (unreported in cysts below the hyoid bone). Although rare, TGDCs should be included in the differential diagnosis of congenital neck masses in neonates who present with positional, intermittent, or progressively worsening obstructive respiratory symptoms. As this case illustrates, infection of the cysts is common, but depending on the location, may not always manifest with visible neck inflammation and swelling. Rapid diagnosis may avoid potentially fatal complications of TGDCs. (Rogelio H. dela Cruz, MD, Matt Barton, Jason Tully, Mercer University School of Medicine, Macon, Ga.)