The term vascular anomaly refers to a wide range of disorders that vary in their presentation and medical seriousness. Although vascular anomalies are growths of vascular tissue and/or extra blood vessels, they are not cancerous. They are generally divided into two distinct categories based on their likelihood to grow:
1. Static (not growing)
2. Proliferative (growing during all or part of their life cycle)
A functional classification of the most common vascular anomalies follows:
1. Those that are present in utero and grow in parallel with the growth of the patient are called static vascular malformations and can affect the capillaries, venules, veins, arteries, and lymphatics alone or in combination. These vessels have developed abnormally during gestation.
2. Proliferative vascular lesions grow disproportionately to the growth of a child, at least during part of his or her development. The most commonly seen proliferative vascular anomalies are:
Hemangiomas are the most frequently seen vascular anomaly. They are not very evident at birth, grow for several months, then stabilize and involute (“diminish”) on their own.
Kaposiform hemangioendotheliomas and tufted angiomas differ from hemangiomas in appearance and clinical presentation. Both of these lesions may be associated with abnormalities in blood counts and clotting factors. A kaposiform hemangioendothelioma (KHE) is often a boggy, usually purplish, sometimes leathery mass, and may develop lymphedema.
A tufted angioma (TA) may appear as a leathery-textured purple red patch on the surface of the skin. Platelets and other factors may be “consumed” within these lesions in a process termed Kasabach-Merritt phenomenon. Biopsy can confirm the diagnosis. These vascular anomalies are discussed in more detail in the following questions.
I knew very little, in fact nothing, about this illness when my daughter was diagnosed with it. I was just scared and astounded by what I saw on my angel’s head. I later learned, through my daughter’s specialist and my own research, that this big red and brown tumor-looking mass on her head was improperly developed blood vessels that grow to become this tumor on the skin.
As the days went by, we learned that this tumor also causes low platelet count and is very dangerous. It is an illness that is very complex and needs to be treated immediately.
The most frequently seen proliferative type of vascular anomaly is a “typical” hemangioma of infancy. Although adults are often told they have hemangiomas in the liver, spleen, spine, or other locations, strictly speaking these are vascular malformations.
Hemangiomas of infancy are rather common and are seen in approximately 7–13% of newborns. Typical hemangiomas are either not evident or appear at birth as a flat pink or white area or a red dot. They increase in size and bulkiness over several months, then gradually involute. The end result after involution depends on the location and other factors related to the type of hemangioma. Fur-ther evaluation or treatment of hemangiomas of infancy depends on the location and/or related complications or impending complications.
A subset of patients with hemangiomas undergo extensive evaluation for associated clinical findings, such as those at risk for PHACES association. PHACES is an acronym for the following abnormalities:
Posterior fossa structural brain anomalies
Hemangiomas in a “segmental” distribution
Sternal or other midline anomalies and/or spinal
Other types of infantile hemangiomas, called RICH (rapidly involuting congenital hemangiomas) and NICH (noninvoluting congenital hemangiomas), undergo a different clinical course. These lesions are all benign and are discussed further in subsequent questions.
Vascular malformations are congenital abnormalities of the blood vessel development. They are not malignant. They can be isolated, involving one vessel type (capil-lary, venous, arterial, lymphatic), or combined type (such as venolymphatic malformation, arteriovenous mal-formation, capillary malformation). While some vascular anomalies are superficial such as a capillary malformation (or a “port wine stain”) involving the skin only, other vascular anomalies are not apparent unless visualized with a radiologic study, often via magnetic resonance imaging (MRI).
Some vascular anomalies may cause symptoms before birth (e.g., high-flow hemangiomas in the liver, high-flow RICH-type hemangiomas, vein of Galen anom-alies in the brain, large arteriovenous malformations). Prenatal ultrasound may also identify related structural anomalies that cause no symptoms such as cysts of lymphatic malformations, vascular malformation-associated skeletal hypertrophy, extra or missing digits, leg asymmetries, and other findings.
Another lesion often mislabeled as a hemangioma is a pyogenic granuloma, which is a small nodule, often on the face, which bleeds. This typically appears in an older child and can be removed by a simple outpatient surgical procedure.
While vascular anomalies can affect a person’s appearance, they generally are not simply cosmetic problems. Proper evaluation is crucial to determine the clinical significance and extent of a vascular anomaly. There are several syndromes associated with vascular malformations that are further described in Question 26.