These are lumps found in the front of the neck in the midline. They are formed due to a persistent thyroglossal duct.
During the development of the thyroid gland before birth, the thyroid gland in the foetus migrates from the bottom of the tongue to its final position in the neck. The path that the thyroid gland takes during its descent into the neck usually disappears, but sometimes persists as a persistent thyroglossal duct.
This persistent duct can give rise to cysts (fluid-filled lumps) or sinuses (blind-ending tracts that lead to the skin).
These lumps usually are hemispherical lumps that appear in the front of the neck in the midline. These lumps tend to move with swallowing and protrusion of the tongue. These lumps are usually painless, however they can become infected and if they do, they may become painful and red.
These lumps are usually treated with surgery. The operation to remove them is called a Sistrunk operation. It involves removal of the lump as well as the middle part of one of the bones in the front of the neck called the hyoid bone which the lump is usually attached to.