Lymphatic malformations (LMs) are rare, non-cancerous growths of the lymphatic system that are present from birth. These malformations arise when lymphatic vessels, which are part of the body’s fluid drainage and immune system, do not form correctly during fetal development. This article explains what lymphatic malformations are and addresses the circumstances under which they might pose significant risks.
Understanding Lymphatic Malformation
The lymphatic system is a complex network of vessels, tissues, and organs. It maintains fluid balance by collecting excess fluid, known as lymph, from tissues and returning it to the bloodstream. This system also serves as a crucial component of the immune system, producing white blood cells that help fight off infections. Lymph travels through lymphatic vessels to lymph nodes, where it is filtered before re-entering circulation.
Lymphatic malformations develop when lymphatic vessels fail to form properly during the early stages of pregnancy. This abnormal development leads to blockages that prevent the proper drainage of lymph fluid, causing the vessels to swell and form spongy clusters of cysts. These malformations are benign and typically present at birth or become apparent by two years of age. They can occur anywhere in the body, though they are most commonly found in the head and neck region.
Lymphatic malformations are classified into different types based on the size of the fluid-filled cysts within them. Macrocystic LMs contain large cysts, often greater than 1 or 2 centimeters in diameter, and may appear as soft, smooth masses under the skin. Microcystic LMs consist of many smaller cysts, typically less than 1 or 2 centimeters, giving them a more spongy or blister-like appearance. Some malformations are a mixed type, containing both large and small cysts.
Assessing Severity and Life-Threatening Risks
Lymphatic malformations are generally not deadly, and most individuals with these conditions can live full lives. The concern regarding their severity often arises from the potential for complications, which are typically associated with the malformation’s size, location, or type, and are relatively rare. The majority of LMs cause issues such as cosmetic concerns, discomfort, or functional impairment rather than posing a direct threat to life.
Serious complications, though uncommon, can occur. These include:
Airway obstruction, particularly if the lymphatic malformation is located in the neck or around the airway, especially in infants. A growing mass in this area can compress the trachea, making breathing difficult.
Severe infection, known as lymphangitis, which can sometimes lead to sepsis if bacteria enter the malformation, especially through skin blebs. Infections can cause significant swelling and pain.
Significant bleeding if the fragile vessels within the malformation rupture, leading to a sudden increase in size and potential internal hemorrhage. This bleeding can cause the malformation to appear bruised or discolored.
Impaired organ function if an LM grows around or compresses a vital organ, such as those in the chest or abdomen.
While these life-threatening outcomes are possible, they are not the typical course for most lymphatic malformations and often arise in specific, complex cases.
Living with Lymphatic Malformation: Management and Outlook
Managing lymphatic malformations often involves a tailored approach based on the malformation’s size, location, and symptoms. For stable lesions that are not causing significant problems, careful observation may be the initial course of action. The primary goals of management are to alleviate symptoms, prevent potential complications, and improve quality of life.
Several treatment options are available:
Sclerotherapy: This widely used procedure, especially for macrocystic lesions, involves injecting a special medication directly into the malformation. This substance irritates the abnormal lymphatic vessels, causing them to scar and shrink, reducing the malformation’s size.
Surgical removal: This may be considered for certain LMs, particularly if sclerotherapy is not suitable or if the malformation is well-defined and can be completely excised without damaging surrounding structures. However, complete surgical removal can be challenging, and recurrence is possible.
Medications: Drugs such as sirolimus are used for complex or widespread lymphatic malformations. Sirolimus can help reduce the size and symptoms of LMs by inhibiting cellular pathways involved in lymphatic vessel growth. This medication is typically taken orally and can be beneficial in cases difficult to treat with other methods.
The long-term outlook for individuals with lymphatic malformations is generally positive, as many LMs can be effectively managed with these various treatments. While recurrence can occur, ongoing medical care and monitoring allow for continued management, enabling most individuals to lead healthy, productive lives.