Background
Capillary hemangiomas are one of the most common benign orbital tumors of infancy. [1] They are benign endothelial cell neoplasms that typically are absent at birth and characteristically have rapid growth in infancy with spontaneous involution later in life. This is in contrast to another known group of childhood vascular anomalies, vascular malformations. Vascular malformations, such as lymphangiomas and arteriovenous malformations, are present at birth and are characterized by very slow growth with persistence into adult life. [2, 3]
Pathophysiology
Capillary hemangiomas are believed to be hamartomatous proliferations of vascular endothelial cells. They now are thought to be of placental origin due to a unique microvascular phenotype shared by juvenile hemangiomas and human placenta. Periorbital capillary hemangiomas follow a similar course to hemangiomas on other parts of the body. They generally exhibit 2 phases of growth, a proliferative phase and an involutional phase. The proliferative phase of rapid growth typically occurs from 8-18 months. Pathologically, it is characterized by an increased number of endothelial and mast cells, the latter being a stimulus for vessel growth. Endothelial cell proliferation returns to normal following the proliferation phase.
The involutional phase is characterized by slow regression of the hemangiomas. One half of all lesions will involute by age 5 years, and 75% will involute by age 7 years. During this phase, mast cell numbers decrease to normal and there is a decrease in endothelial and mast cell activity. These vascular spaces become lined with endothelial cells without muscular support. [4]
Epidemiology
Frequency
United States
As many as 50% of systemic capillary hemangiomas can occur in the head and neck region. Of all the patients who eventually develop capillary hemangiomas, 30% of them have evidence of their presence at birth, whereas 100% have manifest them by age 6 months.
Mortality/Morbidity
Systemic involvement with hemangiomas can be a significant source of morbidity and mortality.
The Kasabach-Merritt syndrome is associated with mortality rates from 30-50%. These patients characteristically present with a consumption coagulopathy and thrombocytopenia secondary to platelet sequestration in large visceral hemangiomas. Disseminated intravascular coagulation may occur. These patients also experience high-output congestive heart failure. Nasopharyngeal hemangiomas can be associated with respiratory obstruction. Surgical intervention often is required in these cases.
PHACES syndrome is associated with large segmental hemangiomas of the head and neck. The acronym refers to P osterior fossa abnormalities (Dandy-Walker malformation), H emangiomas, A rterial lesions, C ardiac abnormalities (coarctation), E ye abnormalities, and S ternal clefting. [1] As a spectrum of severity exists in these patients, they must be closely monitored for progressive cardiovascular and neurovascular deterioration.
The ophthalmic morbidity of hemangiomas is largely related to their space-occupying effects. The most devastating ophthalmic complication of hemangiomas relates to their ability to cause deprivation amblyopia in the affected eye if the lesion is large enough to directly occlude the visual axis. If the lesion is large enough to cause corneal distortion and astigmatism, anisometropic amblyopia will result.
Sex
Female patients outnumber male patients with hemangiomas by a ratio of 3:1.
Age
Capillary hemangiomas are present in approximately 1-2% of neonates. All patients who eventually develop hemangiomas have them by age 6 months.
Prognosis
The prognosis for cosmetic and visual recovery is excellent if treatment is instituted at an appropriate time and careful attention is paid to the visual development. Most lesions involute by age 5 years.
