A Kaposiform hemangioendothelioma (KHE) is a very rare non-cancerous (benign) vascular tumor (affecting the blood vessels) that occurs in children and resembles a birthmark. Most birthmarks go away on their own or cause no medical problems. This type of tumor however requires monitoring and treatment since it involves the vascular system. Signs and symptoms may include: a growing spot (lesion) on the skin, a lesion that swells and becomes painful, and decreased motion in the area around the lesion. KHE tumors are often associated with a more serious condition called Kasabach-Merritt phenomenon. Kasabach-Merritt phenomenon is when blood clots begin to form throughout the body potentially causing organ damage, a loss of platelets (thrombocytopenia) which causes excessive bleeding, and anemia (low levels of iron in the blood). KHE tumors can be diagnosed using MRI tests, ultrasounds, CT scans, blood tests, and by examining the tumor’s cellular appearance. KHE tumors are treatable and medications can be used to treat this kind of tumor. If they are ineffective, additional treatment may be required such as chemotherapy, radiation therapy, or surgery to remove the tumor. Because of the complexity of treatment, multiple specialists may be involved in the care of a KHE tumor.