Multifocal lymphangioendotheliomatosis with thrombocytopenia (cutaneovisceral angiomatosis with thrombocytopenia)

What is multifocal lymphangioendotheliomatosis with thrombocytopenia (MLT)?
Multifocal lymphangioendotheliomatosis with thrombocytopemia is a rare vascular (blood vessel) disorder. MLT is characterized by multiple skin, stomach and intestinal lesions. There may be as few as five or hundreds of lesions present. Most infants have low platelet counts of 30,000-50,000 or less. Platelets help blood to clot properly. It is believed that the platelets are trapped in the abnormal vessels. Many infants and children with MLT will have gastrointestinal (stomach or intestine) bleeding because of the combination of low platelets and abnormal vessels in the stomach and intestines. After the first year of life the children tend to have less thrombocytopenia (low platelet counts) 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 entity, but has been previously misdiagnosed.

What does MLT look like?
The lesions are variable in their size and clinical appearance. Most skin lesions are mistaken for hemangiomas and can be found anywhere on the skin or in the mouth. The lesions on the skin are red to deep purple macules (flat) and papules (raised) and range in size from a few millimeters to 5 cm. Small lesions are 1 to 10 mm in size and are pink-red, round or oval, flat spots/lesions. In the newborn period, very small 1 mm deep blue nodules can also be seen especially on the lower legs. Large lesions measure 1 to 5 cm and are deep purple, often raised above the skin. Larger lesions may have crusting, ulceration and bleeding.

Besides the skin and gastrointestinal tract, multiple other organs can be involved. Lung involvement is the most common, 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 and brain.


Lesions in the Stomach	Skin Lesion	Skin Lesion

What causes MLT?

The cause of MLT is not known.

MLT appears equally in males and females.

MLT is not the result of anything the mother did or did not do during pregnancy.

How is the diagnosis of MLT made?
The diagnosis of MLT is confirmed with a biopsy of a piece of tissue from one of the lesions. This biopsy is usually taken from the skin. Early diagnosis by skin biopsy may be lifesaving. All patients have similar histological findings with thin-walled dilated vessels in the reticular dermis and subcutis.

An endoscopy of the stomach can confirm gastrointestinal involvement. MRI or other imaging tests may be needed to see the involvement of internal organs/structures. Blood tests will be necessary to check if a bleeding disorder is present and to monitor blood cell counts over time. Other tests may be needed depending on the symptoms that are present in the infant.

What kind of care is needed for children with MLT?
Children with MLT need to be closely monitored for an extended period of time by an interdisciplinary health care team that has input from specialties such as dermatologists, gastroenterologists, hematologists, oncologists and surgeons. This team of specialists will form a treatment plan and work together along with the parents in carrying out the plan.

Complications
Most infants with MLT have severe bleeding episodes from the gastrointestinal tract during the first year of life. Blood transfusions are frequently needed with the bleeding episodes.

Treatment
There have been advancements in treatment over the last couple of years. Unfortunately, responses to various treatments for MLT are inconsistent. Blood products such as platelets and/or packed red blood cells may be needed routinely to maintain normal blood cell counts. Drug treatments that have been used are experimental with variable results.

At times, gastrointestinal or other types of surgery may be necessary to remove internal MLT lesions and control bleeding. No one treatment has been found to be most effective in a large group of patients. Additional research is being done to find safe and effective treatments.

MLT has been misdiagnosed
MLT has been misdiagnosed as hemangiomas, blue rubber bleb nevus syndrome, diffuse hemangiomatosis, hereditary hemorrhagic telangioctasia, vascular anomaly with thrombocytopenia and Kasabach-Merritt phenomenon.