Kasabach–Merritt syndrome

Kasabach–Merritt syndrome
Other names	Hemangioma-thrombocytopenia syndrome
Specialty	Hematology

Kasabach–Merritt syndrome (KMS), also known as hemangioma with thrombocytopenia,

Signs and symptoms

Initially a vascular lesion is usually noted on the skin which can be firm and hard (indurated). Areas of tiny red dots (petechiae) can appear around the lesion or on other parts of the body. If the vascular lesion is internal, these petechiae and bruising can be seen on the skin. Bruising and spontaneous bleeding can also occur. The tumors are not hemangiomas. They usually present in young infants, less than three months of age, but have also been reported in the toddler age group. These tumors occur in the extremities, chest, neck, abdomen and pelvis. They infiltrate across tissue and can be aggravated by interventions, infection and trauma. When the tumors associated with KMP are internal such as in the chest or abdomen, they can cause significant illness and can be life-threatening due to bleeding. Internal lesions can take a longer time to diagnose.

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Pathophysiology

Kasabach–Merritt syndrome is usually caused by a hemangioendothelioma or other vascular tumor, often present at birth.^[6][7] Although these tumors are relatively common, they only rarely cause Kasabach–Merritt syndrome.^{[citation needed]}

When these tumors are large or are growing rapidly, sometimes they can trap platelets, causing severe thrombocytopenia. The combination of vascular tumor and consumptive thrombocytopenia defines Kasabach–Merritt syndrome. Tumors can be found in the trunk, upper and lower extremities, retroperitoneum, and in the cervical and facial areas.^[2]

This

The diagnostic workup[8] is directed by the presenting signs and symptoms, and can involve:

• blood counts, clotting studies, and other laboratory testing
• imaging tests (
  MRI, sometimes angiography, and rarely nuclear medicine
  scans)
• Biopsy of the tumor is contraindicated due to risk of bleeding.

Patients uniformly show severe thrombocytopenia, low

Management of Kasabach–Merritt syndrome, particularly in severe cases, can be complex and require the joint effort of multiple subspecialists. This is a rare disease with no consensus treatment guidelines or large randomized controlled trials to guide therapy.^{[citation needed]}

Supportive care

Patient with Kasabach–Merritt syndrome can be extremely ill and may need

Generally, treatment of the underlying vascular tumor results in resolution of Kasabach–Merritt syndrome. If complete surgical resection is feasible, it provides a good opportunity for cure (although it can be dangerous to operate on a vascular tumor in a patient prone to bleeding, even with appropriate surgical subspecialists involved).^[8]

If surgery is not possible, various other techniques^[2] can be used to control the tumor:

• embolization (by interventional radiology) can limit the tumor's blood supply
• external
  compression bandages
  can have similar effects
• certain medications, including:
  • corticosteroids
  • alpha-interferon
  • chemotherapy (e.g. vincristine)
• radiation therapy has been used, often successfully, but now is avoided whenever possible due to the risk of long-term adverse effects (e.g. risk for future cancer).

Prognosis

Kasabach–Merritt syndrome has a mortality rate of about 30%.