Repeated USMLE Questions Step 1- 166

A 5-year-old girl with a mass in her neck is brought to the clinic for an evaluation. Her mother says that this mass appeared 6 months ago and is increasing in size. There is no pain or discomfort. On examination, the mass is in the midline, inferior to the hyoid bone. Laboratory tests reveal normal thyroid panel. Surgery is recommended after a CT scan is performed.

What is the most likely diagnosis?

A-Dermoid cyst

B-Ectopic thyroid gland

C-Lipoma

D-Thyroglossal duct cyst

E-Branchial cleft cyst





Answer:

Normally, thyroglossal cyst disappears during development of the thyroid gland. In some cases, the duct remains in the neck and forms a cyst. It appears in the midline of the neck and is painless. Surgery is recommended to prevent infection if the CT scan shows a normal thyroid gland and thyroglossal duct cyst attached to it. All other options are possible causes but they are less common than thyroglossal duct cyst.

The correct answer is D