Lymphatic malformations are noncancerous clusters of abnormal lymph vessels that form fluid-filled cysts. Treatment focuses on managing symptoms, preventing complications, and improving quality of life. Depending on the size and location of the malformation, approaches range from careful observation to specialized procedures designed to reduce the size of the cysts or remove them entirely.

Treating lymphatic malformations: goals and approaches

When a child is diagnosed with a lymphatic malformation, the primary goal of treatment is to control symptoms and prevent complications that could affect their daily life or harm important body structures. Because these malformations are benign—meaning they are not cancerous—they do not spread to other parts of the body. However, they can grow over time, and this growth can lead to swelling, pain, infection, or pressure on nearby organs such as the eyes, windpipe, or blood vessels.^[1]

Treatment decisions depend heavily on where the malformation is located, how large it is, and whether it is causing problems. A malformation on the neck might interfere with breathing or swallowing, while one on a limb might cause overgrowth or discomfort. Some lymphatic malformations are noticed at birth, while others may not become apparent until childhood or even the teenage years, especially if they are small or located deep inside the body.^[2]

Not all lymphatic malformations require immediate treatment. In cases where the malformation is small, not causing symptoms, and not growing rapidly, doctors may recommend a “watch and wait” approach. This involves regular monitoring through physical exams and imaging tests to ensure the malformation is not changing in a way that could lead to complications. This approach helps avoid unnecessary procedures in children who may never develop symptoms.^[3]

For malformations that do require intervention, there are established treatment methods that have been used for years, as well as newer therapies being studied in clinical trials. The choice of treatment is highly individualized, taking into account the child’s age, overall health, and the specific characteristics of the malformation. Medical teams often include specialists from different fields—such as surgeons, radiologists, and pediatricians—who work together to create the best plan for each patient.^[4]

Standard treatment methods

The most common standard treatments for lymphatic malformations include watchful waiting, sclerotherapy, surgical removal, and medication to manage infections. Each of these approaches has been refined over decades and is recommended by medical guidelines based on the specific situation of each patient.

Watchful waiting and infection management

For many children with small or asymptomatic lymphatic malformations, the best approach is careful observation without active treatment. Doctors schedule regular follow-up appointments and may use imaging tests such as ultrasound, magnetic resonance imaging (MRI), or computed tomography (CT) scans to monitor the malformation over time. These imaging tools allow doctors to see changes in size or structure without invasive procedures.^[5]

One of the most common complications of lymphatic malformations is infection of the skin or soft tissues around the cyst, known as cellulitis. When this happens, the area becomes red, warm, swollen, and painful. Treatment for these infections involves antibiotics, which can be given by mouth if the infection is mild. More serious infections may require hospitalization so that antibiotics can be given directly into the bloodstream through an intravenous line. Prompt treatment of infections is important because repeated infections can cause the malformation to grow larger.^[4]

Sclerotherapy

Sclerotherapy is a procedure in which a doctor injects a special chemical substance directly into the lymphatic malformation. This substance irritates the walls of the abnormal lymph vessels, causing them to stick together and shrink. The procedure is performed by an interventional radiologist, a doctor who specializes in using imaging to guide minimally invasive treatments.^[5]

During sclerotherapy, the child is placed under general anesthesia—a state of deep sleep in which they feel no pain. The doctor uses imaging such as ultrasound to see the malformation and carefully guide a thin needle into the cyst. Once the needle is in place, the sclerosing agent is injected. The entire procedure usually takes less than an hour, and most children can go home the same day or the next morning.^[4]

One treatment session may not be enough to completely shrink the malformation. Many children need multiple sclerotherapy sessions over several months or years. The number of sessions depends on the size and complexity of the malformation. While sclerotherapy can significantly reduce the size of lymphatic malformations and relieve symptoms, there is a chance the cysts may grow back over time.^[5]

Possible side effects of sclerotherapy include swelling, pain, and bruising at the injection site. These symptoms usually improve within a few days. More serious but rare complications can include damage to nearby nerves, blood vessels, or organs, especially if the malformation is located in a complex area such as the neck or chest.

Surgical removal

Surgery to remove a lymphatic malformation is considered when the malformation is causing significant problems or when other treatments have not been successful. The goal of surgery is to remove as much of the abnormal tissue as possible while preserving nearby healthy structures such as nerves, blood vessels, and organs.^[5]

Before surgery, doctors use detailed imaging scans to plan the operation. This planning is crucial because lymphatic malformations often grow in complex patterns and can be closely connected to important structures. During the operation, the surgeon carefully cuts away the malformation. In some cases, it is not possible to remove the entire malformation without risking damage to vital structures, so the surgeon may leave small portions behind.^[4]

Surgery carries risks that vary depending on the location of the malformation. Possible complications include bleeding, infection, scarring, and injury to nearby structures. For malformations in the neck, there is a risk of damage to nerves that control facial movement or the voice. Despite these risks, surgery can provide long-lasting relief for many patients, especially when the malformation is localized and accessible.^[5]

Recovery time after surgery depends on the extent of the operation. Some children may need to stay in the hospital for a few days, especially if the surgery was extensive or involved the airway. Pain medication is given to manage discomfort, and antibiotics may be used to prevent infection. Most children can return to normal activities within a few weeks, though strenuous activities may need to be avoided for a longer period.

Laser therapy and radiofrequency ablation

For superficial lymphatic malformations that involve the skin, laser therapy can be used to treat small fluid-filled bumps called vesicles or lymphatic blebs. These vesicles look like tiny blisters and can leak fluid or blood, causing staining and discomfort. Laser treatment uses focused light energy to destroy these surface lesions without the need for cutting. Multiple sessions are usually required, and the procedure can help improve the appearance of the skin and reduce leakage.^[10]

Radiofrequency ablation uses heat generated by radio waves to destroy abnormal tissue. This technique may be used for certain types of lymphatic malformations, particularly those that are not suitable for sclerotherapy or surgery. Like laser therapy, radiofrequency ablation is a minimally invasive option that can be performed on an outpatient basis.^[10]

Treatment in clinical trials

Because standard treatments do not work for all patients and can sometimes cause complications, researchers are actively studying new therapies for lymphatic malformations. Clinical trials are research studies in which patients receive experimental treatments that are not yet widely available. These trials are carefully designed to test whether new therapies are safe and effective.

Medication-based therapies

One of the most promising areas of research involves medications that target the biological pathways that cause lymphatic malformations to grow. Among these, sirolimus (also known as rapamycin) has shown encouraging results in clinical studies. Sirolimus is a drug that was originally developed to prevent organ rejection after transplant surgery, but researchers discovered it can also slow the growth of abnormal blood and lymph vessels.^[10]

Sirolimus works by blocking a protein called mTOR, which plays a key role in cell growth and division. By inhibiting this protein, sirolimus can reduce the size of lymphatic malformations and improve symptoms. The medication is usually given as a pill or liquid taken by mouth once or twice daily. Treatment may need to continue for months or years to maintain the benefit.

Early results from clinical trials and case reports suggest that sirolimus can be particularly helpful for patients with large or complex lymphatic malformations that cannot be easily treated with surgery or sclerotherapy. Some patients have experienced significant reductions in pain, swelling, and the frequency of infections. However, sirolimus can have side effects, including mouth sores, increased risk of infection, high cholesterol, and effects on blood cell counts. Patients taking sirolimus need regular blood tests to monitor for these side effects.^[10]

Other medications being studied in clinical trials include propranolol and sildenafil. Propranolol is a beta-blocker medication commonly used to treat high blood pressure and certain heart conditions, but it has also shown promise in shrinking some vascular malformations. Sildenafil, which is typically used to treat erectile dysfunction and pulmonary hypertension, may help improve lymphatic drainage by relaxing smooth muscle in blood and lymph vessels. These medications are still in early stages of testing for lymphatic malformations, and more research is needed to determine their effectiveness and safety in this context.^[10]

Understanding clinical trial phases

Clinical trials for new treatments proceed through several phases, each designed to answer specific questions about the therapy. Phase I trials focus on safety. Researchers test the new treatment in a small group of patients to find out what dose is safe and what side effects might occur. If the treatment appears safe, it moves to Phase II trials, which enroll more patients to begin evaluating whether the treatment is effective. Phase II trials also continue to monitor safety. If results are promising, the treatment advances to Phase III trials, which are large studies that compare the new treatment to the current standard of care. Only after a treatment has successfully completed all phases of clinical trials can it be considered for approval by medical authorities.

Patients considering participation in a clinical trial should discuss the potential benefits and risks with their medical team. Clinical trials can provide access to cutting-edge treatments before they are widely available, but they also involve uncertainties since the treatments are still being studied. Participation is entirely voluntary, and patients can withdraw at any time.

Where clinical trials are conducted

Clinical trials for lymphatic malformations are being conducted at specialized medical centers around the world, including in the United States, Europe, and other regions. Many of these centers are associated with large academic hospitals and research institutions. Patients interested in clinical trials can ask their doctor for information about studies that might be appropriate for their situation, or they can search online registries that list ongoing trials.^[10]

Most common treatment methods

• Observation and monitoring
  • Regular physical examinations to check for changes in size or symptoms
  • Imaging tests such as ultrasound, MRI, or CT scans to visualize the malformation over time
  • Recommended for small, asymptomatic malformations that are not growing rapidly
• Infection management
  • Oral antibiotics for mild skin and soft tissue infections (cellulitis) around the malformation
  • Intravenous antibiotics for more serious infections requiring hospitalization
  • Prompt treatment is important to prevent the malformation from enlarging due to repeated infections
• Sclerotherapy
  • Injection of sclerosing agents into the malformation under general anesthesia
  • Performed by interventional radiologists using imaging guidance
  • May require multiple treatment sessions over months or years
  • Aims to shrink the malformation by causing abnormal vessels to stick together
  • Possible side effects include swelling, pain, and bruising at the injection site
• Surgical removal
  • Complete or partial removal of the malformation through surgery
  • Recommended when other treatments fail or when malformation causes significant problems
  • Requires detailed imaging and careful planning to protect nearby structures
  • Risks include bleeding, infection, scarring, and potential damage to nerves or blood vessels
  • Recovery time varies depending on the extent and location of surgery
• Laser therapy
  • Treatment of superficial vesicles (lymphatic blebs) on the skin surface
  • Uses focused light energy to destroy surface lesions
  • Multiple sessions typically required
  • Helps reduce fluid leakage and improve skin appearance
• Radiofrequency ablation
  • Uses heat from radio waves to destroy abnormal tissue
  • Minimally invasive procedure suitable for certain malformations
  • Can be performed on an outpatient basis
• Experimental medication therapies (in clinical trials)
  • Sirolimus (rapamycin): blocks mTOR protein to slow malformation growth, taken orally, requires monitoring for side effects including mouth sores and infection risk
  • Propranolol: beta-blocker medication being studied for vascular malformations
  • Sildenafil: being investigated for potential to improve lymphatic drainage