Hemangiomas are the most common birthmark of infancy. They are benign (not a cancer) stem cell tumors with no genetic or causative factor. Hemangiomas occur in infants only; they never develop in adults. While not well understood, hemangiomas affect girls three to five times more often than boys. Other associated risk factors include prematurity, low birth weight, and twin pregnancy. While hemangiomas can appear anywhere on the body, more than 80% involve the head and neck, including areas around the mouth, eyes, tip of the nose and cheek.
Recent evidence suggests that hemangiomas are stem cell tumors. They are however benign in their behavior. They grow for a finite period and do not spread to other tissues. Most are quite small and innocuous but some can be quite large. At present, there are no known statistics as to what percentage will be problematic.
In general there are two types of hemangioma:
Focal Hemangiomas: These are the most common and grow as solitary tumors. They typically grow rapidly in the first few weeks of life and then the growth rate slows. Most of the growth is done by the age of 6 – 7 months. Focal hemangiomas grow in specific sites, known as sites of predilection. They are commonly found in skin or just beneath it. They can also grow in the parotid salivary gland or the breast bud. Focal hemangiomas can be entirely superficial, in which case they are a reddish color, deep in which case the lesion is a bluish color, or compound, with both superficial and deep components.
Segmental Hemangiomas: As their name implies, segmental hemangiomas grow to involve one or more segments of the face and body. This relates to the development of the fetus which takes place segmentally. Their involvement is thus more widespread. Segmental hemangiomas behave differently in that their growth pattern differs. They also grow rapidly in the first few weeks of life, but they can continue to grow for much longer periods of time. It is not unusual for a segmental hemangioma to grow for up to 2 years. These hemangiomas ulcerate more frequently and can be locally more destructive. In about 30% of cases, there are other associated developmental abnormalities. These are collectively known as PHACES syndrome. Each of the letters in this syndrome stands for a developmental abnormality. It is important to note that it is uncommon for all of these abnormalities to be present in any one child. Most children with this syndrome will have 2 or 3 of these abnormalities. It is however imperative that all children with a segmental hemangioma be investigated for PHACES syndrome.Up to 30% of children with segmental hemangiomas may have PHACES syndrome.
PHACES syndrome ia an acronym:
P. Posterior fossa abnormalities
A. Arterial abnormalities
C. Cardiac abnormalities
E. Eye abnormalities
S. Sternal defect and or supraumbilical raphe