A thyroglossal duct cyst (TGDC) is a common congenital anomaly that arises from incomplete closure of the thyroglossal duct, which is a duct that connects the thyroid gland to the tongue during embryonic development. As a result, a cystic structure forms in the neck, typically in the midline, that can cause swelling, discomfort, and infection. In this article, we will discuss in detail the definitions and types of thyroglossal duct cysts.
- Definition of thyroglossal duct cyst:
A thyroglossal duct cyst is a fluid-filled sac that forms in the neck due to the persistence of the thyroglossal duct, which is a structure that connects the developing thyroid gland to the base of the tongue. Normally, the thyroglossal duct disappears by the end of the embryonic period, but in some cases, it may persist and give rise to a cyst later in life. The cyst usually appears as a midline neck mass that moves up and down when the patient swallows or sticks out their tongue.
- Types of thyroglossal duct cyst:
There are three types of thyroglossal duct cysts, each with its own characteristics and management.
a) Simple cyst:
A simple thyroglossal duct cyst is a benign, fluid-filled sac that is usually located in the midline of the neck. It is the most common type of TGDC and typically presents as a painless swelling that moves up and down with swallowing or tongue protrusion. Simple cysts may become infected, leading to pain, redness, and fever. Treatment involves surgical removal of the cyst and the tract connecting it to the base of the tongue to prevent recurrence.
b) Infected cyst:
An infected thyroglossal duct cyst is a simple cyst that has become inflamed and infected due to bacterial invasion. It typically presents as a painful, red, and tender mass in the neck, which may be associated with fever and malaise. Treatment involves drainage of the pus and antibiotic therapy to control the infection. Surgical excision of the cyst and tract is usually deferred until the infection has resolved.
c) Papillary carcinoma:
Papillary carcinoma is a rare type of cancer that may arise from the cells lining the thyroglossal duct. It is usually diagnosed in adults and may present as a midline neck mass that is firm, fixed, and grows slowly over time. It may also be associated with lymph node involvement and distant metastasis. Treatment involves surgical removal of the cyst, the tract, and any involved lymph nodes, followed by radioactive iodine therapy and long-term surveillance.
Causes
There are several potential causes of TGDCs
- Congenital: One of the primary causes of TGDCs is congenital. The development of these cysts may be due to a failure of the thyroglossal duct to close properly during fetal development.
- Incomplete excision of the thyroglossal duct: Another potential cause of TGDCs is incomplete removal of the thyroglossal duct during surgery. If even a small portion of the duct remains after surgery, it can potentially lead to the development of a cyst later on.
- Persistent thyroglossal duct: As mentioned earlier, the thyroglossal duct is supposed to disappear during fetal development. However, in some cases, the duct may persist and lead to the formation of cysts later in life.
- Abnormal migration of thyroid tissue: In rare cases, thyroid tissue can migrate to the base of the tongue during fetal development. This can lead to the formation of a TGDC later in life.
- Infection: In some cases, infection may be the cause of a TGDC. This can occur if bacteria or other pathogens enter the thyroglossal duct and cause inflammation.
- Obstruction of the duct: If the thyroglossal duct becomes blocked, it can lead to the formation of a cyst. This obstruction can occur due to a variety of factors, including a tumor or other growth.
- Trauma: Trauma to the neck or throat can potentially cause the development of a TGDC. This may occur if the trauma damages the thyroglossal duct or surrounding tissues.
- Hormonal imbalances: Thyroid hormone imbalances can lead to the formation of cysts. This is because the thyroid gland is involved in regulating hormones throughout the body, and imbalances can disrupt normal development.
- Genetic factors: In some cases, TGDCs may be caused by genetic factors. This may be due to inherited mutations that affect the development of the thyroid gland or other structures in the neck.
- Radiation exposure: Radiation exposure can potentially cause the development of a TGDC. This is because radiation can damage the thyroid gland and surrounding tissues, leading to the formation of cysts.
- Autoimmune disorders: Autoimmune disorders can potentially lead to the development of TGDCs. This is because these disorders can cause inflammation and damage to the thyroid gland and surrounding tissues.
- Environmental factors: Exposure to certain environmental toxins or pollutants may increase the risk of developing a TGDC. However, more research is needed to fully understand the relationship between environmental factors and cyst formation.
- Chronic inflammation: Chronic inflammation of the thyroid gland or surrounding tissues can potentially lead to the formation of cysts. This is because inflammation can cause tissue damage and scarring, leading to the development of cysts.
- Drug interactions: Certain medications or drug interactions may increase the risk of developing a TGDC. However, more research is needed to fully understand the relationship between medication use and cyst formation.
- Age: TGDCs are most commonly diagnosed in children and young adults. This may be due to the fact that the thyroglossal duct is most active during fetal development and early childhood.
Symptoms
Most common symptoms of a thyroglossal duct cyst.
- Swelling in the neck The most common symptom of a thyroglossal duct cyst is a swelling or lump in the neck. The cyst can develop anywhere along the thyroglossal duct, from the base of the tongue to the thyroid gland in the neck. The swelling may be noticeable when you swallow, speak or turn your head.
- Pain in the neck A thyroglossal duct cyst can cause pain or discomfort in the neck, especially if it becomes infected or inflamed. The pain may be mild or severe, and it may be constant or intermittent.
- Redness and warmth around the cyst In some cases, a thyroglossal duct cyst can become infected, causing redness and warmth around the cyst. This can be a sign of inflammation and may require medical attention.
- Fever If the cyst becomes infected, it can cause a fever. A fever is a sign that the body is trying to fight off an infection. If you have a fever along with a thyroglossal duct cyst, you should see a doctor as soon as possible.
- Difficulty swallowing A thyroglossal duct cyst can put pressure on the throat, making it difficult to swallow. This can be especially problematic if the cyst becomes large or if it is located near the base of the tongue.
- Difficulty breathing In rare cases, a large thyroglossal duct cyst can put pressure on the airway, making it difficult to breathe. This can be a medical emergency and requires immediate attention.
- Hoarseness or voice changes If the cyst is located near the vocal cords, it can cause hoarseness or changes in the voice. This is because the cyst is putting pressure on the vocal cords, making it difficult to speak normally.
- Ear pain A thyroglossal duct cyst can cause ear pain if it is located near the ear canal. This is because the cyst can put pressure on the nerves that supply the ear, causing pain.
- Headaches If the cyst is located near the base of the skull, it can cause headaches. This is because the cyst is putting pressure on the nerves and blood vessels in the area.
- Nausea and vomiting If the cyst becomes infected, it can cause nausea and vomiting. This is because the body is trying to get rid of the infection.
- Bad breath If the cyst becomes infected, it can cause bad breath. This is because the infection can produce a foul-smelling odor.
- Fatigue If the cyst becomes infected, it can cause fatigue. This is because the body is fighting off the infection, which can be draining on your energy levels.
- Difficulty opening the mouth If the cyst is located near the base of the tongue, it can make it difficult to open the mouth. This is because the cyst is putting pressure on the muscles and nerves in the area.
- Neck stiffness If the cyst becomes infected, it can cause neck stiffness. This is because the infection can cause inflammation in the neck, making it difficult to move your head.
Diagnosis
Common diagnostic tools and tests used to identify and manage thyroglossal duct cysts.
- Physical exam: A thorough physical exam by a healthcare provider may reveal a palpable, painless lump in the midline of the neck that moves when the patient swallows or protrudes their tongue.
- Medical history: A detailed medical history can help determine when the lump first appeared, how it has changed over time, and if the patient has experienced any symptoms.
- Ultrasound: An ultrasound is a non-invasive imaging test that uses high-frequency sound waves to produce images of the inside of the body. It can help identify the size, location, and characteristics of the cyst and can differentiate it from other neck masses.
- Fine needle aspiration (FNA): An FNA is a minimally invasive procedure that uses a thin needle to withdraw a small sample of fluid or tissue from the cyst for analysis. This can help confirm the diagnosis and rule out other conditions.
- Blood tests: Blood tests may be ordered to check thyroid function and to rule out other underlying conditions that could be contributing to the cyst.
- CT scan: A CT scan uses X-rays and computer technology to produce detailed images of the inside of the body. It can help identify the extent of the cyst, its relationship to surrounding structures, and any abnormalities in nearby organs.
- MRI: An MRI uses a powerful magnet and radio waves to produce detailed images of the body. It can help identify the size, location, and extent of the cyst and its relationship to surrounding structures.
- Thyroid scan: A thyroid scan uses radioactive iodine to visualize the thyroid gland and can help differentiate the cyst from other thyroid abnormalities.
- Biopsy: A biopsy involves removing a small sample of tissue from the cyst for analysis. This may be done during surgery or as an outpatient procedure.
- Thyroid function tests: Thyroid function tests measure levels of thyroid hormones in the blood and can help identify underlying thyroid disorders that may be contributing to the cyst.
- Barium swallow: A barium swallow is an imaging test that uses X-rays and contrast material to visualize the throat and esophagus. It can help identify any swallowing difficulties caused by the cyst.
- Endoscopy: Endoscopy involves inserting a thin, flexible tube with a camera and light on the end into the throat or nasal cavity to visualize the cyst and surrounding structures.
- Laryngoscopy: Laryngoscopy is a procedure that uses a thin, flexible tube with a camera and light on the end to visualize the larynx and vocal cords. It can help identify any abnormalities caused by the cyst.
- Thyroglossal duct cystogram: A thyroglossal duct cystogram involves injecting contrast material into the cyst to visualize its shape and location on X-ray or CT scan.
- Cytology: Cytology involves analyzing cells from the cyst fluid or tissue under a microscope to help identify any abnormal or cancerous cells.
- Immunohistochemistry: Immunohistochemistry involves analyzing tissue samples from the cyst for specific proteins or markers that may indicate the presence of cancer.
Treatment
Here are 20 treatment options for thyroglossal duct cyst:
- Observation: Small TGDCs that are not causing any symptoms may not require any treatment. Instead, the cyst may be monitored over time to ensure that it does not grow in size or become infected.
- Antibiotics: If the TGDC becomes infected, antibiotics may be prescribed to treat the infection and prevent further complications.
- Incision and drainage: In cases of infected TGDCs, the cyst may need to be drained by making a small incision in the skin over the cyst. This procedure can help to alleviate symptoms and prevent the spread of infection.
- Fine needle aspiration (FNA): FNA involves using a thin needle to extract a sample of cells from the cyst for examination under a microscope. This procedure can help to determine if the cyst is cancerous or benign.
- Ultrasound: Ultrasound imaging may be used to evaluate the size and location of the cyst and to rule out the presence of any abnormalities or cancerous growths.
- Thyroid function tests: Blood tests may be used to evaluate thyroid function and rule out the presence of thyroid cancer.
- Sistrunk procedure: This surgical procedure involves removing the cyst, along with the thyroglossal duct and a portion of the hyoid bone. This procedure is typically reserved for larger cysts or cysts that are causing significant symptoms.
- Excision: In some cases, the cyst may be removed by making a small incision in the skin over the cyst and excising the cyst wall.
- Laser ablation: Laser ablation involves using a laser to destroy the cyst and its surrounding tissue. This procedure is typically used for smaller cysts or those that are located in difficult-to-reach areas.
- Radiofrequency ablation: Radiofrequency ablation uses heat to destroy the cyst and its surrounding tissue. This procedure is similar to laser ablation and is typically used for smaller cysts.
- Electrocautery: Electrocautery involves using a small electrical current to destroy the cyst and its surrounding tissue. This procedure is typically used for smaller cysts or those that are located in difficult-to-reach areas.
- Cryotherapy: Cryotherapy involves using freezing temperatures to destroy the cyst and its surrounding tissue. This procedure is typically used for smaller cysts.
- Chemical cauterization: Chemical cauterization involves using a chemical agent to destroy the cyst and its surrounding tissue. This procedure is typically used for smaller cysts.
- Injection sclerotherapy: Injection sclerotherapy involves injecting a solution into the cyst to shrink it and prevent it from growing further. This procedure is typically used for smaller cysts.
- Marsupialization: Marsupialization involves creating a small opening in the cyst and stitching the edges of the cyst wall to the edges of the skin. This procedure allows the cyst to drain and prevents it from reoccurring.
- Endoscopic surgery: Endoscopic surgery involves using a small camera and surgical instruments to remove the cyst. This procedure is typically used for smaller cysts or those that
- Modified Sistrunk procedure: The modified Sistrunk procedure involves removing the entire cyst and the central portion of the hyoid bone, as well as the thyroglossal duct and any associated tract. This is considered the gold standard for the treatment of TGDC.
- Endoscopic-assisted Sistrunk procedure: The endoscopic-assisted Sistrunk procedure uses a small camera and specialized instruments to remove the cyst and the central portion of the hyoid bone. This approach can result in less scarring and a faster recovery.
- Robotic-assisted Sistrunk procedure: The robotic-assisted Sistrunk procedure uses a surgical robot to remove the cyst and the central portion of the hyoid bone. This approach can provide greater precision and control.
- Transoral robotic surgery (TORS): TORS involves removing the cyst through the mouth using a surgical robot. This can be an effective treatment for small cysts.
- Transoral endoscopic thyroidectomy vestibular approach (TOETVA): TOETVA involves removing the thyroid gland or cyst through a small incision in the mouth. This can be an effective treatment for small cysts.
- Carbon dioxide (CO2) laser surgery: CO2 laser surgery uses a laser to remove the cyst through a small incision. This can be an effective treatment for small cysts.
- Microdebrider-assisted excision: Microdebrider-assisted excision uses a small suction device and a cutting tool to remove the cyst through a small incision. This can be an effective treatment for small to moderate-sized cysts.
References
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