A thyroglossal duct cyst is a fluid-filled sac or cyst that forms in the neck due to the failure of the thyroglossal duct to close during fetal development. The thyroglossal duct is a tube-like structure that forms early in the development of the thyroid gland, connecting it to the tongue. As the thyroid gland descends, the duct usually disappears, leaving only a small remnant called the pyramidal lobe. However, in some cases, the duct remnants may persist and become fluid-filled cysts.
Thyroglossal duct cysts typically present as a painless, soft, and smooth swelling in the midline of the neck, just above the thyroid gland. The size of the cyst can vary from tiny to several centimeters in diameter. It may be apparent at birth or develop later in childhood or adulthood. If the cyst becomes infected, it can cause pain, tenderness, and redness.
Diagnosis of a thyroglossal duct cyst is usually done through physical examination and imaging techniques, such as ultrasound or CT scan. The treatment of choice is surgical removal of the cyst, along with the entire thyroglossal duct and sometimes part of the hyoid bone to prevent recurrence.
While thyroglossal duct cysts are generally benign, it is important to remove them promptly to avoid complications such as infection, abscess formation, or rarely, the development of thyroid cancer within the cyst. The prognosis after surgical removal is usually excellent, with a low likelihood of recurrence.
