Conditions + Treatments

Kasabach-Merritt in Children

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Contact the Vascular Anomalies Center


If your child has been diagnosed with Kasabach-Merritt phenomenon (KMP), a complication in which certain vascular tumors trap and destroy platelets, we understand that you are very concerned about your child’s health. You probably have a lot of questions about this complex condition and the vascular tumors that cause it.

Here’s what you need to know about Kasabach-Merritt phenomenon:

  • Kasabach-Merritt phenomenon is a serious complication because platelets help form blood clots to stop bleeding. If your child doesn’t have enough of them, your child may have an increased risk of bleeding.
  • Kasabach-Merritt phenomenon is never caused by common infantile hemangiomas.
  • It’s associated with the following tumors:
  • KMP is associated with larger, more aggressive or more deeply invading benign vascular tumors. As doctors shrink the tumor with medications, KMP goes away.
  • We treat the underlying tumor that’s associated with KMP, not the KMP itself. Please see details about treatments in the links above for your child’s specific tumor.

How Children’s Hospital Boston approaches Kasabach-Merritt phenomenon
Because Kasabach-Merritt phenomenon and the associated vascular tumors are so rare, we recommend that children with KMP be evaluated by an expert vascular anomalies center. In articles and on the web, KMP is confused with any blood test related to clotting or bleeding in a patient with a birthmark, hemangioma or vascular tumor. This is incorrect and leads to the wrong diagnosis and ineffective treatment plans in some cases.

Here at Children’s Vascular Anomalies Center, we have the world’s largest database of children whose vascular tumors have caused Kasabach-Merritt phenomenon. When doctors anywhere in the world have questions about whether a child’s birthmark may be a vascular tumor that could lead to Kasabach-Merritt phenomenon, they often call us. Our physicians have treated more children with Kasabach-Merritt phenomenon than any other hospital in the world—which means that your child will get expert care from experienced physicians.

The database

Children’s Vascular Anomalies Center has the largest database in the world of children who have experienced Kasabach-Merritt phenomenon — currently more than 125 cases of vascular anomalies with KMP. As our database grows, it will help shine more light on this rare and often misunderstood condition.

Kasabach-Merritt phenomenon: Reviewed by Cameron C. Trenor III, MD,
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