Lymphatic Malformation

Lymphatic malformations are clusters of abnormal lymph vessels that form fluid-filled cysts under the skin or within body tissues. These noncancerous growths develop before birth and most commonly appear on the head and neck, though they can occur anywhere in the body except the brain.

Table of contents

• What are lymphatic malformations?
• Other names
• What causes lymphatic malformations?
• Types of lymphatic malformations
• Signs and symptoms
• Where they occur
• How are they diagnosed?
• Possible complications
• Treatment options

What are lymphatic malformations?

A lymphatic malformation is a cluster of abnormal lymph vessels (thin tubes that carry fluid through the body) that form a growing, spongy mass of cysts (fluid-filled sacs). These are noncancerous growths that appear as unusual masses but are not dangerous in most cases.^[1]

The lymphatic system is a network of tubes, organs, and tissues that is part of the body’s immune system. It helps fight infection and keeps fluid levels balanced in the body by collecting and returning lymph (a clear, pale yellow fluid) from body tissues back to the bloodstream.^[1]

Lymphatic malformations grow because the lymph fluid in the abnormal vessels cannot drain properly and these vessels are usually separate from the normal lymphatic system. This causes the vessels to swell, which is known as a flare. The malformations also contain fragile, misshapen veins in their walls that bleed easily. When a lymphatic malformation fills with blood or lymph fluid, the pooling stretches the vessels and cysts, making the mass grow larger.^[1]

Lymphatic malformations can affect only the lymph vessels and result in cysts that range in size from microscopic to large masses the size of small water balloons. Veins and lymph vessels travel together in the body, and often blood leaks into the dilated lymph vessels.^[4]

lymphangiomas, cystic hygromas

Other names

Lymphatic malformations were previously called lymphangiomas or cystic hygromas.^[2] These terms are still sometimes used, especially to describe specific types of malformations.

What causes lymphatic malformations?

Lymphatic malformations form before birth during pregnancy. They are caused by problems in the formation and development of the lymphatic vessels when the baby is growing in the womb. The lymphatic system begins to develop from special cells on blood vessels during the sixth week of pregnancy. Between the 12th and 14th weeks, lymph sacs connect with each other to form a network of small vessels and tubes. When these sacs fail to communicate properly with the rest of the lymphatic system during development, the vessels can become blocked and enlarged, causing fluid to build up.^[2][7]

Lymphatic malformations are not caused by any drug, medication, or environmental exposure during pregnancy. They are not inherited from parents, though they are more common in babies of older mothers and in babies with certain chromosome problems such as Down syndrome, Noonan syndrome, or Turner syndrome.^[2][3]

Most lymphatic malformations are identified at birth or in early childhood. Some may not be noticed until the teenage years or early adulthood if they are small or located inside the body.^[2]

Types of lymphatic malformations

Healthcare providers classify lymphatic malformations based on the size of the abnormal lymph channels, their depth, and their location. There are three main types.^[2][3]

Macrocystic lymphatic malformation

Macrocystic lymphatic malformations (also called cystic hygromas or lymphangiomas) have large, stretched vessels and cysts filled with lymph, blood from internal bleeding, or both. These are large, soft masses most often found deep within the neck, face, armpits, or chest. They appear as fluid-filled cysts that look like soft, smooth masses under normal or blue-colored skin.^[1][2][3]

These masses can grow so large that they block the baby’s airway at birth. Half of all babies born with this type of malformation have a chromosomal disorder such as Down syndrome, Noonan syndrome, or Turner syndrome.^[3]

Microcystic lymphatic malformation

Microcystic lymphatic malformations (also called lymphangioma circumscriptum) are spongy and have small vessels and tiny cysts. These are smaller, pimple-sized cysts most often found closer to the surface of the skin. They are sponge-like and look like an area of swelling.^[1][2][3]

Microcystic lymphatic malformations may have fluid-filled bumps called vesicles or lymphatic blebs over the affected area. These are small, raised skin bumps containing clear lymphatic fluid that look like tiny blisters or blood blisters. They may also become dark purple or black when blood leaks into them. The fluid in them starts out clear and colorless, but will turn dark red if blood leaks into it. These skin bumps can cause bleeding from the skin surface.^[1][2]

This type of malformation may be present at birth (congenital) or appear a few years later (acquired).^[3]

Mixed lymphatic malformation

Mixed lymphatic malformations are a combination of macrocystic and microcystic types. Lymphatic malformations of the neck region often contain this combination of micro and macrocysts.^[3][4]

Signs and symptoms

A lymphatic malformation usually appears as a growing, spongy-feeling lump or mass. The skin over the malformation may have small bubbles or blisters on the surface. A child can have more than one lymphatic malformation, but they are usually in the same area of the body.^[1]

Lymphatic malformations typically do not cause pain and should not be itchy. These cysts are almost always noncancerous and are rarely life-threatening. However, symptoms can occur depending on the size and location of the malformation.^[3]

A child with a lymphatic malformation may have:^[1]

• Overgrowth and swelling in affected areas such as lips, tongue, jaws, cheeks, arms, legs, fingers, or toes
• Pain and swelling of the lymphatic malformation
• A tendency to injure the malformation, causing bleeding, which can happen with very mild trauma or even with no known trauma
• A soft, smooth lump or mass that gets larger quickly
• Bleeding and infection

Less commonly, the vesicles are filled with milky fluid called chyle.^[1]

When skin blisters and crusts rupture, leakage of bloody lymph may give the appearance of significant bleeding. The drainage is mostly bloody water that does not clot like normal blood, which can be troublesome for parents and patients.^[4]

Symptoms related to location

Some symptoms are related to the specific area of the body affected. Lymphatic malformations can put pressure on nearby body parts such as the eyes, windpipe, or blood vessels as they grow.^[1][3]

Lymphangiomas that affect the:^[3]

• Bones: May cause bone loss or bone overgrowth
• Chest: May cause chest pain, shortness of breath, or wheezing
• Eyes: May cause bulging eyes or double vision
• Digestive tract or pelvis: May cause bladder blockage, constipation, or frequent infections
• Mouth or windpipe: May cause feeding problems, shortness of breath, speech issues, or trouble swallowing

Lymphatic malformations of the neck region can cause significant airway problems when present in newborns.^[4]

Where they occur

Lymphatic malformations can form inside skin, fat, connective tissue, joints, organs, or bones. They can form anywhere in the body except the brain and are most common in the head and neck area.^[1][2]

Lymphatic malformations may involve any part of the body and can involve multiple body areas, though they are usually found in only one area. Lymphatic malformations of the lower limbs may be apparent at birth or may not appear until later in life.^[2][3][4]

Abdominal lymphatic malformations are rare and make up less than 5% of all lymphatic malformations. Within the abdomen, these malformations can arise from solid organs such as the pancreas, liver, or spleen, or from the mesentery (tissue that attaches intestines to the abdominal wall), the space behind the abdominal organs, or the gastrointestinal tract.^[7]

Some lymphatic malformations are inside the body and cannot be seen without specialized imaging.^[2]

• Head and neck
• Face
• Armpits
• Chest
• Arms and legs
• Mouth and tongue
• Abdominal organs
• Bones

How are they diagnosed?

Most lymphatic malformations are identified at birth or shortly after. Healthcare providers use medical history and physical examination to diagnose a lymphatic malformation.^[2]

Imaging tests may be needed to confirm the diagnosis or to see the full extent of the malformation. These imaging studies include:^[2][5]

• Ultrasound: Uses sound waves to create pictures. Lymphatic malformations appear as masses with multiple fluid-filled spaces. This test can help distinguish lymphatic malformations from simple cysts.
• Magnetic Resonance Imaging (MRI): Uses magnets and radio waves to create detailed images. The fluid in lymphatic malformations appears dark on some images and bright on others. Different signal patterns can suggest whether the fluid contains blood or a milky substance.
• Computed Tomography (CT scan): Uses X-rays to create cross-sectional images. On CT scans, lymphatic malformations appear as masses with dividing walls, and contrast material enhances the walls and dividers of the malformation.

These imaging studies help doctors understand the size, location, and characteristics of the malformation before deciding on treatment.^[7]

Possible complications

While most lymphatic malformations are not life-threatening, they can cause complications depending on their size and location.^[3]

Infections

Lymphatic malformations can put patients at higher risk for infections. Infection of the skin or soft tissues (called cellulitis) may occur around the malformation. Signs of infection include redness, warmth, pain, swelling, and drainage. These infections require antibiotic treatment. If oral antibiotics are not sufficient, patients may need to be admitted to the hospital for intravenous antibiotics.^[2][4]

Lymphatic malformations may swell and become tender or painful when the body is fighting an infection. Infections should be identified and treated promptly to prevent the effects of the malformation from worsening.^[5]

Growth and swelling

As lymphatic malformations grow, they may put pressure on nearby vital organs and body parts. This can interfere with normal function, such as breathing or feeding, which can be life-threatening in some cases.^[1][5]

Abdominal complications

Complications of abdominal lymphatic malformations can occur as they increase in size and include twisting of the intestines, gastrointestinal blockage, and bleeding in the bowel.^[7]

Treatment options

Not all lymphatic malformations require treatment. Most lymphangiomas do not need treatment unless they cause problems or are likely to interfere with normal function.^[3][5]

Current treatment options include:^[10]

Observation

Many small lymphatic malformations that do not cause symptoms can simply be watched over time without active treatment.

Sclerotherapy

Sclerotherapy is a procedure carried out by a specially trained doctor called an interventional radiologist. The doctor shrinks the lymphatic vessels by injecting a special substance through the skin under general anesthesia. This treatment may require several sessions, and even then, the malformation might grow again.^[5]

Surgery

Sometimes lymphatic malformations can be removed safely through surgery. Detailed scans are needed to plan the operation. There will be scarring after the operation, as with all surgery. Surgery may be recommended when malformations cause significant symptoms or complications.^[5]

Other treatments

Additional treatment options include:^[10]

• Radiofrequency ablation: Uses heat energy to destroy abnormal tissue
• Laser therapy: Uses focused light to treat surface lesions
• New therapies are emerging, including medications such as sildenafil, propranolol, and sirolimus

The choice of treatment depends on the size, location, and type of lymphatic malformation, as well as the symptoms it causes. Healthcare providers work with families to determine the best approach for each individual child.