Thyroglossal Duct Cyst

Photoclinic

A 2-year-old boy was brought to the  emergency department by his mother after she had noted a progressive swelling on the anterior part of his neck. Earlier that day, the boy had been seen at a pediatric clinic with a 1‑week history of fever, cough, and nasal congestion for which he received a diagnosis of respiratory syncytial virus.

Upon examination in the emergency department, pertinent physical findings included a 3 × 2.5-cm, midline, nonerythematous and nontender swelling on the anterior part of his neck, which moved with swallowing and with protrusion of his tongue. He had no stridor or respiratory distress.

Ultrasonography of the neck showed a complex, thick-walled fluid collection in the anterior neck, midline at the level of the thyroid cartilage, which was suspicious for an infected thyroglossal duct cyst (TGDC). Results of a complete blood count were unremarkable.

The patient completed a 10-day course of clindamycin and later underwent thyroglossal cyst removal surgery (the Sistrunk procedure). The postsurgical pathology report revealed thyroglossal duct remnants with no evidence of malignancy.

TGDC is the most common congenital midline lesion of the neck.¹ It derives from an embryonic thyroglossal duct remnant, which usually involutes at 5 to 10 weeks of gestation. The location of a TGDC may extend from the base of the tongue at the foramen cecum to the central portion of the hyoid bone. The most common site is between the thyroid gland and the hyoid bone.² 

TGDCs usually are diagnosed in children from 2 to 10 years of age, but one-third of cases are diagnosed in early adulthood.³ Males and females are equally affected. The most common inheritance pattern is autosomal dominant.⁴ Although the majority of TGDCs are within 2 cm of the midline, some are positioned more laterally.⁵

Infants with TGDCs at the foramen cecum typically develop symptoms within the first few weeks of life. These patients commonly present with stridor, feeding difficulties, coughing, cyanotic episodes, failure to thrive, and breath-holding spells.⁶ Diagnosis can be made at the bedside with direct laryngoscopy. In children, a TGDC typically presents as a painless midline neck mass that often appears after an upper respiratory tract infection. Most TGDCs have some degree of infection or inflammation at presentation. Vertical movement of the mass with swallowing and tongue protrusion is a pathognomonic sign.⁷

The list of differential diagnoses includes dermoid cysts, sebaceous cysts, cervical thymic cysts, lipomas, branchial cleft cysts, ectopic thyroid tissue, thyroid nodules, lymphatic malformations, hemangioma, midline lymphadenopathy, and salivary gland tumors.

Ultrasonography is the preferred imaging study for diagnosing a TGDC.⁸ Identifying the location of the thyroid gland helps with diagnosis, because patients with a TGDC and an ectopic thyroid gland may have hypothyroidism. Computed tomography or magnetic resonance imaging may be more helpful in diagnosing a lingual TGDC. Cysts in the tongue base may be differentiated from an undescended lingual thyroid by using radionuclide scanning. In the rare occasion of malignant transformation in children, the TGDC usually changes into a papillary adenocarcinoma.^7,9

An infected TGDC should be managed initially with broad-spectrum antibiotics targeting oral flora,¹⁰ followed by the Sistrunk procedure once the infection has resolved. This definitive treatment procedure excises the cyst to its origin at the foramen cecum, including the central portion of the hyoid bone. Recurrence of TGDC after a Sistrunk procedure is rare.^2,11

References:

1. Al-Khateeb TH, Al Zoubi F Congenital neck masses: a descriptive retrospective study of 252 cases. J Oral Maxillofac Surg. 2007;65(11):2242-2247.

2. Türkyilmaz Z, Sönmez K, Karabulut R, et al. Management of thyroglossal duct cysts in children. Pediatr Int. 2004;46(1):77-80.

3. Brown RL, Azizkhan RG. Pediatric head and neck lesions. Pediatr Clin North Am. 1998;45(4):889-905.

4. Schader I, Robertson S, Maoate K, Beasley S. Hereditary thyroglossal duct cysts. Pediatr Surg Int. 2005;21(7):593-594.

5. Hechtman DH, Shapiro DS. Congenital lesions: thyroglossal duct cysts, branchial cleft anomalies, and cystic hygromas. In: Fischer JE, ed. Mastery of Surgery. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2007:335-342.

6. Thimann D, Huang C. Lingual thyroglossal duct cyst. Consultant for Pediatricians. 2012;11(9):283.

7. Leung AKC. Lumps and bumps in children: cysts. Consultant for Pediatricians. 2012;11(5):134-236.

8. Huoh KC, Durr ML, Meyer AK, Rosbe KW. Comparison of imaging modalities in pediatric thyroglossal duct cysts. Laryngoscope. 2012;122(6):1405-1408.

9. Peretz A, Leiberman E, Kapelushnik J, Hershkovitz E. Thyroglossal duct carcinoma in children: case presentation and review of the literature. Thyroid. 2004;14(9):777-785.

10. Al-Dajani N, Wootton SH. Cervical lymphadenitis, suppurative parotitis, thyroiditis, and infected cysts. Infect Dis Clin North Am. 2007;21(2):523-541.

11. Hirshoren N, Neuman T, Udassin R, Elidan J, Weinberger JM. The imperative of the Sistrunk operation: review of 160 thyroglossal tract remnant operations. Otolaryngol Head Neck Surg. 2009;140(3):338-342.