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Lymphatic malformations can affect any area of the body (except the brain), but most often affect the head and neck.
Lymphatic malformations are rare, non-malignant masses that consist of fluid-filled channels or spaces that are thought to be caused by the abnormal development of the lymphatic system.
These malformations usually appear at birth or at two years of age.
When they are evident at birth (congenital), lymphatic malformations tend to be soft and spongy masses.
The specific symptoms and severity of lymphatic malformations vary according to the size and specific location of the malformation.
Lymphatic malformations, regardless of size, can cause a functional deterioration of nearby structures or organs and the deformation of affected areas.
The lymphatic system functions as part of the immune system and helps protect the body against infections and diseases.
It consists of a network of tubular channels (lymphatic vessels) that carry a thin aqueous fluid, known as lymph, from different areas of the body to the bloodstream.
The lymph accumulates between the cells of the tissues and contains proteins, fats and certain white blood cells known as lymphocytes.
As the lymph moves through the lymphatic system, it passes through a network of lymph nodes that help the body attack the sources of infections such as viruses, bacteria, and inflammation (Antigens).
Groups of lymph nodes are found throughout the body, in the neck, under the arms (armpits), in the elbows and in the chest, abdomen and groin.
The lymphatic system includes the spleen, which filters spent red blood cells and produces lymphocytes, and the bone marrow, which is the spongy tissue inside the bone cavities that make blood cells.
Several different terms were used once to describe the conditions now grouped under the general term “hygromas or lymphatic malformations”.
These terms include cystic hygroma, lymphangioma, cavernous lymphangioma, cystic lymphangioma, circumscribed lymphangioma, lymphangiomatosis, macrocystic and microcystic lymphatic malformation.
These terms have been abandoned because some of the obsolete terms imply a relationship with cancer.
Lymphatic malformations are not cancerous and there is no known risk of malignant transformation.
Types of hygromas
- The Lymphangioma: A group of lymphatic vessels that form a mass, is a cavernous lymphangioma that contains very enlarged lymphatic vessels.
- Cystic hygroma: A large cyst or lymph fluid pocket that results from blocked lymphatic vessels and may contain several lymphatic vessels connected together.
Most cystic hygromas originate in the neck area, and some lymphangiomas can arise in other parts of the body, also in the cheeks, mouth and surrounding tissue.
Lymphatic malformations are present from birth, but sometimes they are not detected at that stage. Sometimes lymphatic malformations spread through the surrounding tissues and affect the proper development of these tissues.
Lymphatic malformations usually enlarge and become infected after the onset of a condition of the upper respiratory tract.
Lymphatic malformations may be seen in children who have certain chromosomal abnormalities and genetic conditions, such as Down syndrome and Turner syndrome.
Causes
The exact cause of lymphatic malformations is unknown.
Lymphatic or hygromasic malformations are the result of anomalies in the development of the lymphatic vascular system during embryonic growth.
In a large number of patients, lymphatic malformations are positive for an activating mutation in the PIK3CA gene.
This is a somatic (non-hereditary) mutation isolated from lymphatic endothelial cells, which lines the fluid-filled channels.
It is known that the PIK3CA gene plays a role in the regulation of cell growth, through signaling through the PI3K / mTOR pathway, which controls many of the elementary cellular processes for the formation and growth of cancer cells.
Five different point mutations have been identified in the DNA of the lymphatic malformation tissue.
However, it is not clear whether mutations in the PIK3CA gene cause only lymphatic malformations.
Lymphatic malformations can occur in the uterus as part of other syndromes, these include: Noonan syndrome, Turner syndrome and Down syndrome.
In general, lymphatic malformations detected in this context are absent at the time of birth.
Lymphatic malformations are also a feature of Cloves syndrome and Klippel-Trenaunay syndrome.
Cystic hygromas can also develop due to environmental factors such as viral infections that passed from the mother to the baby during pregnancy and exposure to drugs or alcohol during pregnancy.
symptom
Generally, the symptoms of lymphatic malformations arise from the compression or obstruction of nearby structures.
Lymphatic malformations can involve any tissue.
They are usually found in only one area of the body (localized), but occasionally they can be scattered (diffuse).
When lymphatic malformations are disseminated in the bone and soft tissue, the condition can be called lymphangiomatosis.
Lymphatic malformations usually grow slowly as the patient grows, but from time to time they get smaller spontaneously.
Certain events such as puberty, infections, traumas or hemorrhages in a lymphatic malformation can cause them to grow rapidly.
The specific symptoms that develop depend on the size and exact location of a lymphatic malformation.
Lymphatic malformations are associated with excessive growth (hypertrophy) and swelling of the affected area, including the lips, tongue, jaws, cheeks, arms, legs, fingers or toes.
Malformations that affect the tongue or trachea can cause shortness of breath ( dyspnea ), difficulty speaking and difficulty swallowing ( dysphagia ) and feeding problems.
When symptoms are associated with the (eye) orbit, double vision (diplopia) or displacement of the eyeball (proptosis) may occur.
Lymphatic malformations affecting the chest can cause wheezing, chest pain, chest tightness, shortness of breath, difficulty breathing and potential compromise of the airways.
Lymphatic malformations that affect the gastrointestinal tract or pelvis can cause constipation , bladder obstruction, recurrent infection or protein loss.
Bone injuries can be associated with bone overgrowth or bone loss.
Certain complications can occur with hygromas that include recurrent inflammation or bleeding (hemorrhage) in the malformation.
When the hygromas become inflamed, swell and the skin of the affected area becomes red and hot, this is known as cellulitis.
Recurrent cellulitis can cause pain and deformation of the affected area.
Some patients with hygromas have an abnormally low number of lymphocytes that make them prone to cellulitis.
Bleeding in a lymphatic malformation can cause rapid pain, hardening, swelling or enlargement of the affected area.
Radiographic lymphatic malformations have been categorized into three subtypes: macrocystic, microcystic or mixed.
The macrocystic and microcystic lymphatic malformations are differentiated by the size of the portion of the malformation that contains the fluid.
The macrocystic type is formed by large cysts, more than 2 centimeters in diameter and the microcystic type is formed by smaller cysts or soft tissue enlargement without cyst formation.
The majority of lymphatic malformations have macrocystic and microcystic portions and, histologically, no differences are observed between these categories.
The macrocystic lymphatic malformations are characterized by a single or multiple fluid-filled sacs and are cysts that occur, commonly in the area of the neck.
The macrocystic lymphatic malformations generally form large and smooth translucent masses that can affect any area of the neck or thorax.
The overlying skin may have a bluish color.
Although macrocystic lymphatic malformations usually appear in the back of the neck, they can originate but less frequently near the armpits, in the groin, in the back of the abdominal cavity, in the chest wall or in the hip or region of the neck. coccyx.
The macrocystic lymphatic malformations can potentially be very large, even large enough to obstruct the airway at the time of delivery.
Microcystic lymphatic malformations that contain clear fluid or blood (hemorrhagic) usually grow slowly, in proportion to a growing child.
The microcystic lymphatic malformations can thicken or swell and cause enlargement of the soft tissues and surrounding bones.
They can be found in any area of the skin or mucous membrane.
Diagnosis
The diagnosis of Higroma can often be made before birth, through ultrasound.
Through this examination the high frequency sound waves produce an image of the developing fetus, the doctor will request an amniocentesis if he notices a cystic hygroma during an ultrasound, to verify genetic abnormalities in the fetus.
After birth, the diagnosis of a lymphatic malformation is made based on a physical examination along with a detailed history of the patient.
Advanced imaging techniques such as magnetic resonance imaging, computed tomography, and ultrasound can be used to evaluate the extent of a hygroma after birth.
An MRI uses a magnetic field and radio waves to produce cross-sectional images of organs and body tissues.
During the computed tomography scan, a computer and x-rays are used to create a film that shows cross-sectional images of certain tissue structures.
Treatment
The specific treatment of the hygroma will be determined by the doctor based on the following:
- The age of the child, his general state of health and his medical history.
- The scope of the condition.
- The child’s tolerance for specific medications, procedures or therapies.
- Expectations for the development of the condition.
The treatment of lymphatic malformations addresses the specific symptoms that are evident in each individual.
In lymphatic malformations of the head and neck, staging systems have been developed that help guide treatment planning and predict the outcome of treatment.
The main therapeutic options to treat a lymphatic malformation are percutaneous drainage, surgery, sclerotherapy , laser therapy and radiofrequency ablation.
These different treatment options can be used in various combinations.
In rare cases, the lymphatic malformations disappeared without any therapy, that is, by spontaneous resolution.
Percutaneous drainage is a procedure during which an incision is made in a lymphatic malformation and the fluid is usually drained through a catheter or similar device.
Percutaneous drainage is often done along with surgery or sclerotherapy, since the drained cyst fluid can accumulate again.
In general, macrocystic lymphatic malformations can be treated effectively and are not repeated.
Mixed and microcystic lymphatic malformations are usually more difficult to treat because they do not respond to conventional therapies.
There is a risk of recurrence of lymphatic malformations regardless of the choice of treatment.
Mixed and microcystic lymphatic malformations are more likely to recur and may require repeated therapies.
In some cases, lymphatic malformations require lifelong therapy.
Sclerotherapy is a procedure in which a solution, called a sclerosing agent, is injected directly into the macrocystic lymphatic malformation.
This solution eventually causes them to shrink.
Most of the macrocystic lymphatic malformations of moderate size can easily be treated with sclerotherapy.
Although the popularity of sclerotherapy for lymphatic malformations is increasing, there is no specially favored or agreed upon sclerosing agent.
Agents that have been used include alcohol, bleomycin, picinabil (OK-432), doxycycline, acetic acid and hypertonic saline.
Sclerotherapy may require multiple sessions to be effective, especially in extensive malformations.
Some lymphatic malformations, especially those located in an area of the body, can be surgically removed (excised).
The objective of surgery to eliminate a lymphatic malformation is to recover the function of an affected area and avoid complications and deformations.
The exact location of a lymphatic malformation, such as proximity to a vital organ, may dictate only a partial removal of the malformation and may be sufficient to prevent complications.
In some cases, the participation of vital organs or structures makes it impossible to surgically remove a lymphatic malformation.
Laser therapy is sometimes used to treat people with lymphatic malformations that affect the skin or mucous membranes.
Multiple treatments spaced over time may be required, and laser therapy is generally used in combination with other treatment options.
Radiofrequency ablation has been used to treat individuals with superficial malformations of the skin or lymphatic mucosa.
During this procedure, a small needle is inserted into the hygroma.
The needle is used to administer a high-frequency alternating current (radiofrequency waves) that destroys (excises) the tissue of the affected lymph vessels.
Initial reports show a marked improvement or complete resolution of individuals treated with radiofrequency ablation.
More research is needed to determine the long-term safety and efficacy of this potential therapy and others for people with lymphatic malformations.
Medical therapy with the medications sirolimus or sildenafil can be used to treat both localized and diffuse lymphatic malformations.
Sirolimus is most often used to treat cancer and has only recently been prescribed to treat lymphatic malformations.
This medication is taken orally and works by inhibiting cell growth by targeting the PI3K / mTOR pathway.
It has been shown, in a small number of patients, to reduce lymphatic malformations.
This medication allows the walls of the blood and lymph vessels to relax, and this in some way leads to less fluid accumulation.
Clinical trials are being conducted to establish dosing guidelines and compare these medications with other treatment options.
Additional treatment may be necessary for people with lymphatic malformations depending on the degree to which the malformation affects normal breathing, feeding and speech.
For example, airway compromise and difficulty breathing may require treatment with a tracheotomy .
If the diet is altered, a modified diet and a gastrostomy tube may be necessary .
Some children may require reconstructive surgery for the bones of the jaw due to excessive growth, caused by the deformation of a lymphatic malformation.
Infections may require antibiotics.
Analgesics and anti-inflammatory medications can also be used in some cases.
Related disorders
The symptoms of the following disorders may be similar to those of hygromas.
The comparisons can be useful for a differential diagnosis.
Gorham’s disease is a rare bone disorder characterized by bone loss (osteolysis) associated with excessive growth (proliferation) of blood vessels (vascular) or lymphatics.
Affected people experience progressive destruction and bone resorption.
Multiple bones may be involved, but areas commonly affected by Gorham disease include the pelvis, shoulder, spine, ribs, jaws and skull.
It can cause pain and swelling in the affected area.
The bones affected by Gorham’s disease are prone to fracture.
The severity of Gorham’s disease can vary from one individual to another and can cause deformation and functional disability.
There are a variety of similar conditions or lesions that can be confused with a lymphatic malformation: Langerhans cell histiocytosis, lymphangioleiomyomatosis, and congenital pulmonary lymphangiectasia.
Some benign and malignant tumors, including hemangiomas, lipomas and gliomas, are often mistaken for lymphatic malformations.
A variety of skin conditions can be confused with a lymphatic malformation that is limited to the skin.
Complications
The main potential complications of cystic hygromas are:
- Recurrent growths
- Bleeding
- Infections in the affected area
- Damage to the muscles, nerves or tissues where the hygroma forms.
However, the outlook for babies with cystic hygromas is usually good if the growths appear after birth.
