A soft, painless lump felt in the neck may be a congenital cyst. These cysts form when certain structures that should normally disappear during development in the womb are left behind, and they are benign. They are usually not noticed at birth; years later, generally after an infection, they enlarge and become obvious.
What is a congenital neck cyst?
During a baby’s development, the neck region contains temporary ducts, clefts and layers of tissue. Once development is complete, these are expected to close and disappear. A duct that fails to close, or a piece of tissue left behind, can form a closed sac filled with fluid or soft material, that is, a cyst. The cyst may remain silent for years; it is noticed by chance or when it swells.
Main types
- Branchial cleft cysts: Sit on the side of the neck, below the angle of the jaw and along the front edge of the large neck muscle.
- Thyroglossal duct cysts: Lie exactly in the midline of the neck, around the hyoid bone; they move upwards on swallowing and when the tongue is stuck out.
- Dermoid cysts: Cysts containing skin-like tissue, mostly located in the midline, under the chin or in the floor of the mouth.
- Rarer types: Remnants of thymus tissue, lymphangiomas arising from lymph vessels (cystic hygroma) and lesions of vascular origin are also counted among congenital neck masses.
Symptoms
- A slowly growing, soft, usually painless lump in the neck
- Sudden enlargement, redness and pain of the lump during an upper respiratory tract infection
- If the cyst becomes infected, discharge through the skin or a constant leak from a small opening (fistula)
- With large cysts, a feeling of pressure on swallowing or, rarely, difficulty breathing
Diagnosis
Diagnosis begins with the history and a hands-on examination; the position and movement of the cyst give important clues to its type. Ultrasound is the first imaging method and shows whether the lump is a cyst or a solid mass. Magnetic resonance imaging (MRI) or computed tomography (CT) may be requested to see the deep extensions of the cyst and its relationship with the neighbouring vessels and nerves. In thyroglossal cysts, it is also important to confirm that the thyroid gland is in its normal position and working. In doubtful cases, a sample may be taken with a fine needle.
Treatment approach
Congenital cysts do not disappear on their own; medication only settles the inflammation and does not remove the cyst. The permanent solution is surgical removal of the cyst in one piece, together with the duct or tract it arises from. Where possible, surgery is planned for a period when the cyst is quiet and free of inflammation. The details of the procedure vary with the type of cyst and are described on the relevant pages.
When should you see a doctor?
- If you have noticed a lump in your neck that has not gone away for a few weeks
- If the lump repeatedly enlarges and shrinks with infections
- If there is redness, warmth, pain or discharge over the lump
- If difficulty swallowing or breathing accompanies it
In adults, every newly appearing lump in the neck should be assessed by examination and imaging before it is assumed to be a benign cyst.
Frequently asked questions
Can a congenital neck cyst turn into cancer?
These cysts are benign, and a malignant change in them is extremely rare. Even so, every newly noticed lump in the neck should be assessed by examination and imaging.
If the cyst is congenital, why did it appear in adulthood?
The cyst has been present since birth but stayed small and silent. It usually enlarges and becomes obvious after an upper respiratory tract infection, and only then is it noticed.
Will antibiotic treatment make the cyst go away?
Antibiotics only settle the inflammation of the cyst; because the cyst wall remains in place, the swelling can return over time. The permanent solution is surgical removal of the cyst.
This page is general information. Decisions about diagnosis and treatment are made for you personally, and only after an examination. If you have symptoms, see a doctor.