Kasabach-Merritt syndrome

What is Kasabach-Merritt? syndrome?

Kasabach-Merritt syndrome is characterized by the combination of:

  • Rapid growth vascular tumor
  • Thrombocytopenia (low platelets)
  • Microangiopathic hemolytic anemia (destruction of red blood cells)
  • Consumptive coagulopathy (impaired coagulation).

Blood clotting disorder results from platelets and other blood clotting factors being used (consumed) within the tumor.

What Causes Kasabach-Merritt Syndrome?

Kasabach-Merritt syndrome is caused by kaposiform hemangioendotheliomas, with tufted angiomas and sometimes other vascular tumors. Kasabach-Merritt syndrome was previously thought to be caused by a large infant hemangiomas (also known as cavernous hemangiomas or capillary hemangiomas) however, this is not the case.

Kaposiform hemangioendotheliomas
Kaposiform hemangioendotheliomas are typically solitary tumors that appear in the soft tissues of the extremities, head and neck or retroperitoneum. They are usually seen in babies younger than 2 years old, although cases have been reported in adults. They do not spread (metastasis) but can cause serious problems due to local growth, heart failure or the associated Kasabach-Merritt phenomenon. There are few reports of kaposiform hemangioendotheliomas without Kasabach-Merritt syndrome. Kaposiform hemangioendotheliomas usually return over time but do not go away completely.

Tufted angiomas
Tufted angiomas usually present before 5 years of age, although they can occur throughout life. They appear as brown, red, or purple areas of the skin and are firm to the touch. They are often painful. Spontaneous regression is unusual.Most tufted angiomas do not cause Kasabach-Merritt syndrome and metastasis is rare.

What research should be done?

Kasabach-Merritt syndrome may be suspected in an infant with vascular growth and evidence of easy bleeding or bruising. Blood tests may include a complete blood count and film, clotting screen, and fibrin Degradation products. Magnetic resonance, angiographyand biopsy It can be done but it will depend on the baby's clinical condition.

What is the treatment for Kasabach-Merritt syndrome?

Various specialists may be involved in the care of a child with Kasabach-Merritt syndrome, including pediatricians, dermatologists, hematologists, surgeons, and radiologists. Administration of blood products to correct coagulopathy may be ineffective. Several treatments have been used for Kasabach-Merritt syndrome, including vincristine and systemic steroids, as well as interferon alpha, cyclophosphamide, aspirin, and dipyridamole, and radiotherapy. Recently, oral sirolimus (which has anti-angiogenic activity) has been reported to be remarkably effective in some cases. Embolization and surgical removal may also be considered.

Treating Kasabach-Merritt syndrome can be difficult. It is estimated to have a mortality of around 20%.