Kaposiform Hemangioendothelioma: Causes, Symptoms, and Treatment
Medically reviewed by Harsha Moole, MD, Internal Medicine. Last reviewed: October 2, 2026.
What kind of doctor treats Kaposiform Hemangioendothelioma?
A pediatrician or family doctor is usually the first to notice the problem. Care then involves specialists, such as a hematologist-oncologist who treats blood disorders and tumors. Many children are treated at centers with experience in rare vascular tumors. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What it is
Kaposiform hemangioendothelioma is a rare growth made up of abnormal blood vessel cells. It is not cancer in the usual sense, but it can act a bit like a cancer by growing into nearby tissue. It is most often found in babies and young children and usually does not spread to distant parts of the body, though it can cause serious problems where it sits.
Symptoms
The most common sign is a lump under the skin or in a soft tissue area, such as an arm or leg. It may look purple, red, or skin colored and can grow over time. A serious complication is Kasabach-Merritt phenomenon, where the tumor traps platelets, the blood cells that help clotting, causing easy bruising, dark red spots, or serious bleeding that needs urgent care.
Causes and who gets it
Doctors do not know exactly what causes kaposiform hemangioendothelioma. It is not passed down from parents, and nothing a parent did or did not do causes it. Most cases appear in infancy.
How doctors diagnose it
A doctor will examine the lump and ask about the child's health history. Imaging tests, such as ultrasound or MRI, show how big and deep the growth is. Blood tests can check platelet levels to see whether Kasabach-Merritt phenomenon is present.
Treatment
Treatment depends on the size and location of the growth and whether there are blood problems. Small growths that cause no symptoms may simply be watched. When treatment is needed, doctors often use sirolimus, a drug that slows the growth of abnormal blood vessel cells. Some growths shrink while others need long-term treatment.
When to see a doctor
See a doctor if a child has a lump that grows, changes color, or does not go away. Seek care right away for easy bruising, tiny red or purple spots, bleeding that will not stop, or unusual tiredness, which can signal a low platelet count.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. Either one can order initial imaging and blood work, monitor platelet counts, and manage follow-up visits, and would typically refer the patient to a specialist or vascular anomalies center for treatment decisions, then coordinate care between visits.
Common questions
Is kaposiform hemangioendothelioma cancer?
It is considered a borderline tumor. This means it is not clearly benign but does not usually spread to distant organs. It can, however, grow into nearby tissue and cause serious blood problems. Doctors treat it with that risk in mind.
Does it go away on its own?
Some growths shrink slowly over years, but this varies from person to person. Many children need medicine to control the growth or to manage blood complications. Regular follow-up with a specialist is common.
Can adults get it?
Yes, though it is much more common in babies and young children. Adults who develop a soft tissue lump should have it examined.
What is Kasabach-Merritt phenomenon?
It is a complication where the tumor destroys platelets, the blood cells that help with clotting. This can lead to easy bruising and serious bleeding. It is treated as a medical emergency.
Sources
- NIH Genetic and Rare Diseases Information Center - Kaposiform hemangioendothelioma
- NCBI Bookshelf - Kasabach-Merritt Syndrome
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
