Vascular Anomalies Center - Children's Hospital Boston

300 Longwood Avenue
Boston, MA 02115
(617) 355-6000

Clinical Services (Vascular Anomalies Center):

Rare Vascular Tumors

Kasabach-Merritt phenomenon

Kasabach-Merritt phenomenon is a bleeding disorder that results from a platelets trapped in a vascular tumor (thrombocytopenia). Fibrinogen and some other clotting factors are also depleted. It is associated with kaposiform hemangioendothelioma (KHE) and tufted angioma, but never occurs with common infantile hemangioma.

An infant with Kasabach-Merritt phenomenon is at risk for hemorrhage and a rapid increase in the size of the tumor, with possible compression of vital structures. The mortality rate may be as high as 20 percent. The bleeding disorder resolves with effective treatment or spontaneous regression of the tumor.

Kaposiform hemangioendothelioma (KHE)

KHE is an uncommon vascular tumor that can be present at birth or appear in early infancy. Compared with common hemangiomas, KHE occurs less frequently in the head and neck region; typical locations are the trunk, shoulder, thigh, and retroperitoneum.

The involved skin is deep reddish-purple, tense, and shiny. Tiny purple or red spots and a bruise-like discoloration overlie and are adjacent to the tumor. This bruised appearance may falsely suggest a diagnosis of child abuse.

KHE is often associated with the Kasabach-Merritt phenomenon, as noted above bleeding disorder. Retroperitoneal KHE is associated with a high mortality rate. KHE sometimes responds to corticosteroid; often vincristine is needed to control the tumor and correct the bleeding disorder.

Tufted angioma

Tufted angioma is a rare vascular tumor that occurs in early childhood and is sometimes present at birth. These tumors appear as small red or purple patches on the skin of the neck and upper trunk, grow slowly and, in some patients, can ultimately cover large areas of the upper trunk and neck.

A large tufted angioma can present with Kasabach-Merritt phenomenon. So-called "acquired" tufted angioma appears in childhood as a localized, hard, dull red or purple patch of several centimeters in size. This form is not associated with platelet-trapping.

Epithelioid hemangioendothelioma

Epithelioid hemangioendothelioma is a rare, low-grade malignant vascular tumor that occurs in various sites, including the bone, liver, and lungs. The treatment for this tumor, which originates in the endothelium (the layer of cells that line blood and lymphatic vessels, as well as the heart), includes surgical removal or, if the tumor is inaccessible, chemotherapy and radiation therapy.

Hemangiopericytoma

Hemangiopericytoma is a vascular tumor that can present in a spectrum from benign to malignant (cancerous). Most occur in adults and arise in deep sites. In infancy, the tumor is called infiltrating myofibroma these tumors usually spontaneously regress.



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