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The University of Chicago Medicine - Comer Children's Hospital

Types of Vascular Anomalies: Kasabach-Merritt Phenomenon

Kasabach-Merritt phenomenon (KMP) is a rare, potentially life-threatening condition that occurs when certain fast growing vascular tumors [kaposiform hemangioendothelioma (KHE) or tufted angioma (TA)] trap and destroy platelets, interfering with blood clotting and raising the risk of serious bleeding. Kasabach–Merritt phenomenon is also known as hemangioma thrombocytopenia syndrome.

Signs and Symptoms

Patients diagnosed with kaposiform hemangioendotheliomas or tufted angiomas are monitored for the development of Kasabach-Merritt phenomenon. Signs and symptoms of KMP include:

  • Rapidly growing reddish-brown lesions on the head and neck, trunk, shoulder area, and legs
  • Pain
  • Bruising
  • Prolonged bleeding after injury or break in the skin (e.g., needle stick)

Diagnosis

Although the presence of KHE or TA indicates a risk of developing Kasabach-Merritt phenomenon, an accurate diagnosis of KMP requires a blood test to measure platelet counts. A physician may also perform a physical exam to check for abdominal masses and to look for signs of bleeding, such as excessive bruising or "pinpoint" brown spots that indicate small blood vessel bleeding. Imaging tests such as CT and MRI may also be performed.

Treatments

In many cases, several different types of treatment are required to manage and treat Kasabach-Merritt phenomenon. These therapies aim to:

  • Address low platelet count
  • Control blood clotting
  • Eradicate the associated KHE or TA tumor


Treatments may include:

  • Surgery to remove the tumor
  • Embolization of the tumor to limit its blood supply
  • Medications
  • Radiation therapy (in rare cases)
  • Plastic or dermatologic surgery for reconstructive purposes

About Our Program

The Vascular Anomalies Program at the University of Chicago Medicine Comer Children's Hospital offers an integrated and comprehensive approach to the diagnosis, care and management of hemangiomas and vascular malformations. Our multidisciplinary team of pediatrics experts works together to educate families and to evaluate and treat children with all types of these vascular lesions. » Read more about our program and our team. 

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