Multifocal lymphangioendotheliomatosis with thrombocytopenia (MLT)

Multifocal lymphangioendotheliomatosis with thrombocytopenia is a rare blood vessel disorder. People with MLT have multiple skin, stomach and intestinal lesions. Some people have as few as five lesions, but some people have hundreds of them. These lesions can lead to abnormal blood vessels.

In addition to the lesions, most infants with MLT also have thrombocytopenia (low blood platelet counts) with counts ranging from 30,000 to 50,000 or even lower. Normal platelet levels are more than 150,000. Experts believe that platelets get trapped in the abnormal vessels, which leads to low counts. Platelets are important because they help the blood clot properly. Without good clotting, serious bleeding can occur both inside and outside the body.

The combination of blood vessels and low platelet count can lead to gastrointestinal (stomach or intestine) bleeding. After the first year of life, the children tend to have less thrombocytopenia and bleeding. Another term that is used in medical literature to describe this disorder is cutaneovisceral angiomatosis with thrombocytopenia.

MLT is a relatively newly described condition, but we believe it has existed but has been previously misdiagnosed.

What does MLT look like?

The lesions are variable in their size and clinical appearance, and they can be found on the skin or in the mouth. The skin lesions are often mistaken for hemangiomas.

About the lesions:

• The lesions on the skin are red to deep purple macules (flat lesions) and papules (raised lesions)
• They range in size from a few millimeters to 5 cm
• Small lesions measure 1 to 10 mm in size and are pink-red, round or oval, flat spots/lesions.
• Large lesions measure 1 to 5 cm and are deep purple, often raised above the skin
• Larger lesions may have crusting, ulceration and bleeding
• In newborns, very small 1 mm deep blue nodules can also be seen, especially on the lower legs

Besides the skin and gastrointestinal tract, multiple other organs can be involved. Lung involvement is the most common organ involved, seen in 7 out of 17 of reported patients. Other reported organ involvement includes:

• Synovium-membrane lining a cavity (biopsy-proven)
• Muscle
• Bone
• Bone marrow
• Spleen
• Brain

Lesions in the stomach	Skin lesion	Skin lesion

What causes MLT?

Experts have not yet found a cause for MLT. What we do know is that:

• MLT appears equally in males and females.
• MLT is not the result of anything the mother did or did not do during pregnancy.

How do you diagnose MLT?

Your child's doctor will confirm a diagnosis of MLT with a biopsy of a piece of tissue from one of the lesions. In most cases, the doctor will take the biopsy from the skin. Early diagnosis by skin biopsy may be lifesaving.

Tests to aid in diagnosis

• To confirm gastrointestinal involvement, the doctor may perform an endoscopy, which is a test that allows the doctor to see inside the gastrointestinal tract.
• A radiologist also may perform an MRI or other imaging tests to see the involvement of internal organs and structures
• The doctor will also order blood tests to check for the presence of a bleeding disorder and to monitor blood cell counts over time
• Other tests may be needed, depending on your child's symptos

What kind of care will my child with MLT require?

Children with MLT need to be closely monitored for an extended period of time by a health care team that includes experts from different specialties. The team at Children's includes a specialists from dermatology, gastroenterology, hematology, oncology and surgery. Together, we will develop a plan to treat your child in the best way possible.

Complications of MLT

One of the most serious effects of MLT is severe bleeding episodes from the gastrointestinal tract during the first year of life. If your child has gastrointestinal bleeding, he or she likely will need blood transfusions during bleeding episodes.

Treatment options for MLT

Experts have made promising treatment advances in the last couple of years, but some kids do better than others with the treatment. Therefore, your child's treatment may not be the same as another child with the same disorder.

Some treatment possibilities are:

• Your child may need blood products, such as platelets and/or packed red blood cells, to maintain normal blood cell counts.
• There are some drug treatment options that have been used, but they are experimental and have variable results.
• Your child may need surgery, including gastrointestinal surgery, to remove internal MLT lesions and control bleeding.
• Though we are always working toward better treatment options, not one treatment has been found to be most effective in a large group of patients.

Researchers at Children's and the Medical College of Wisconsin have established a national patient registry for MLT. The goal of this registry is to collect patient data from around the world to better understand the cause and natural history of this rare disease, and eventually discover better treatments or even a cure for MLT. Contact Beth Drolet, MD, at bdrolet@mcw.edu for more information.

MLT has been misdiagnosed

Because MLT is a complex disorder with many and varying symptoms, it has been misdiagnosed as many conditions, including:

• Hemangiomas
• Blue rubber bleb nevus syndrome
• Diffuse hemangiomatosis
• Hereditary hemorrhagic telangiectasia
• Vascular anomaly with thrombocytopenia
• Kasabach-Merritt phenomenon