A 7-year-old boy is brought to the office for evaluation of a neck mass. A week ago, the patient was taken to an urgent care clinic for nasal congestion and sore throat. The symptoms resolved after a few days, but his parents noticed a persistent neck swelling. The patient has no prior medical conditions, and his immunizations are up to date. On physical examination, he appears well and is well nourished. Neck examination shows a mildly tender, 2-cm, midline mass that moves up when the patient swallows. Which of the following is the most likely cause of this patient's lesion?

Question

A 7-year-old boy is brought to the office for evaluation of a neck mass.  A week ago, the patient was taken to an urgent care clinic for nasal congestion and sore throat.  The symptoms resolved after a few days, but his parents noticed a persistent neck swelling.  The patient has no prior medical conditions, and his immunizations are up to date.  On physical examination, he appears well and is well nourished.  Neck examination shows a mildly tender, 2-cm, midline mass that moves up when the patient swallows.  Which of the following is the most likely cause of this patient's lesion?

Quizplus · Accepted Answer

11ec160b_373b_a647_9249_b93346578dcc_MD0001_00 This patient has a thyroglossal duct cyst (TDC), which presents as a midline mass that characteristically moves superiorly with protrusion of the tongue or swallowing. A TDC is often detected when it becomes secondarily infected after an upper respiratory tract infection, leading to erythema and tenderness. It may also be noted incidentally during evaluation of throat or neck symptoms. The thyroid gland is formed as an outpouching from the pharyngeal epithelium at the base of the tongue. It then descends to the base of the anterior neck via the thyroglossal duct, which extends from the foramen cecum on the dorsal surface of the tongue to the superior border of the thyroid isthmus. If the duct fails to atrophy normally, a TDC can develop from the epithelial remnants within the duct. Because the tract connects to the base of the tongue, protrusion or swallowing causes the TDC to move superiorly. Ectopic thyroid tissue may also form and can reside anywhere along the thyroglossal duct's path. (Choice A) A paraganglioma is a neuroendocrine tumor that arises from extraadrenal, autonomic paraganglia (eg, carotid body paraganglia) due to the abnormal migration of neural crest cells. Carotid body paragangliomas typically present as lateral neck masses. (Choice B) Cervical implantation of thymic tissue can result in ectopic thymic cysts, which are rare lesions that may develop along the descent of the thymus (angle of the jaw to the mediastinum). They are typically unilateral (left more often than right) rather than midline. (Choice C) A cystic hygroma results from abnormal lymphatic development, leading to dilated lymphatic vessels. It presents at birth as a soft mass at the posterior base or lateral aspect of the neck. It would not typically be at the midline or rise with swallowing. (Choice E) A branchial cleft cyst is an embryologic remnant of branchial arch structures that presents as a lateral (rather than midline) neck mass. A sinus tract or fistula may also be present. (Choice F) Trapping of skin structures (eg, hair follicles, sebaceous glands) along embryonic fusion lines results in the formation of a dermoid cyst within the subcutaneous tissue. It presents as a midline neck mass but, in contrast to this patient's neck mass, does not move with tongue protrusion or swallowing. Educational objective: Thyroglossal duct cysts form from epithelial remnants of the thyroglossal duct along the path of thyroid descent. They present as midline masses that rise with swallowing or tongue protrusion. __________ References: Thyroglossal duct cysts: anatomy, embryology and treatment. (http://www.ncbi.nlm.nih.gov/pubmed/23689821) Congenital cystic lesions of the head and neck. (http://www.ncbi.nlm.nih.gov/pubmed/21807315) Congenital cystic neck masses: embryology and imaging appearances, with clinicopathological correlation. (http://www.ncbi.nlm.nih.gov/pubmed/24629659)

A 7-Year-Old Boy Is Brought to the Office for Evaluation