Lymphatic malformations are sponge-like collections of abnormal channels and spaces that contain clear fluid.
The lymphatic system normally collects excess fluid from the tissues and transports it through a series of small vessels back into the venous system. With a lymphatic malformation, however, transfer of this fluid through these vessels is slowed. The excess fluid accumulates and dilates the vessels, resulting in a swelling of the affected area and sometimes in more extensive enlargement of soft tissues and bones.
These lesions are most commonly seen in the neck and axilla (armpit), but they can involve any area of the body. In certain areas the dilated lymphatic vessels tend to be small, while in other areas, they tend to be large. As with other vascular malformations, lesions may be superficial or deep, and localized or diffuse. They steadily increase in size, although some enlarge more rapidly than others. Conditions such as infection or trauma can result in sudden but temporary enlargement.
Although the exact cause of lymphatic malformations is unknown, they are thought to be caused by errors in the formation and development of blood vessels during fetal development. The cause is not related to any known drug or medication that may have been taken during pregnancy or to any environmental exposure that may have occurred during that time.
There are two types of lymphatic malformations and these are often combined.
- Macrocystic malformations are large, soft, smooth clear masses under normal or bluish skin.
- Microcystic malformations present as small, raised lesions containing clear fluid.
Both macrocystic and microcystic malformations may cause enlargement of any structure (e.g., the lip, cheek, ear, tongue, limb, finger, or toe). Lymphatic malformations in the skin may present as tiny clear bubbles, called vesicles, that sometimes become dark red due to bleeding. Lymphatic malformations confined to skin are referred to as lymphangioma circumscriptum.
Gorham syndrome (also called Gorham-Stout syndrome or vanishing bone syndrome) is a type of lymphatic malformation that involves the bone and surrounding soft tissues. It can be serious, causing significant bone loss and other complications.
Lymphangiomatosis is a term used for diffuse lymphatic lesions that involve vital structures, such as the bone, chest, spleen and gastrointestinal tract.
Spontaneous lymphatic leakage from the skin commonly occurs. As well as being troublesome, this can lead to or be associated with cellulitis (infection of tissue in and beneath the skin). Recurrent cellulitis, which causes pain and cosmetic disfigurement, can also occur and may lead to serious infection. Bacteria may readily enter through open vesicles and quickly spread through tissues affected by these lesions. When this occurs, aggressive antibiotic therapy is essential. Another major complication is bleeding into the lymphatic malformation. This may cause pain and swelling in the area of the malformation.
Additional complications may occur, depending upon the specific area of the body that is affected by the lesion:
- A lesion involving the trachea (windpipe), tongue or chest can cause difficulty breathing.
- A lesion in the gastrointestinal tract (stomach and intestines) can cause protein loss.
- A lesion in the thorax (chest) can cause chylothorax, which is a leakage of lymphatic fluid into the chest cavity. It can also cause heart and lung complications.
- A lesion in the abdomen can cause chylous ascites, which is a leakage of lymphatic fluid into the abdomen.
- A lesion in the bone can cause bony destruction and pain.
Although certain complications cannot be prevented, they can sometimes be diminished. Developing an infection in a lymphatic malformation of the head/neck region is less likely if careful attention is paid to oral hygiene. Teeth should be brushed regularly and thoroughly and should be cleaned by a dental hygienist more frequently than is usual.
Treatment and management of lymphatic malformations include:
- Surgical excision (removal). Some lesions, especially those that are localized, are generally treated by surgical removal. As well, surgical excision may be used as part of an overall treatment plan that includes one or more of the other treatment approaches listed below. When lesions are extensive and surround many vital structures, a surgical approach may be difficult or impossible. Surgical excision cannot be done without some scarring, and years after excision, lymphatic vesicles may become apparent again in or around a scar. Additionally, surgical excision may cause damage to structures involved with the lesion.
- Sclerotherapy (direct injection of an irritating agent). For large macrocystic lesions, sclerotherapy with alcohol, doxycycline, or other drugs causes total or near-total shrinkage in 80% of cases. This treatment has limited effect on microcystic lesions. This approach may result in superficial or deep tissue scarring. Also, in some cases, the lesion may not respond to treatment. In other cases, it may reappear.
- Laser therapy. Depending on the complexity of the lesion, surgical lasers are used selectively with beneficial results. These lasers are generally used as a component of an overall treatment plan that integrates other approaches as well. Laser therapy requires multiple treatments that are spaced over several months. It is done under general anesthesia. This may result in some tissue scarring and/or changes in skin pigmentation. These can sometimes be improved by additional cosmetic procedures.
- Radio frequency ablation. This is a relatively new technique that employs high-energy radio frequency sound waves to selectively destroy superficial lesions. As with other treatment approaches, it may be used as a component of an overall treatment strategy involving several approaches over a period of time. Minor bleeding and infection are the primary risks of this technique.
- Chemotherapeutic agents. Extensive, life-threatening lymphatic malformations that are unresectable are sometimes treated with chemotherapy and other medical treatments.