Infantile hemangiomas (IH) are a type of benign vascular tumour that occurs in babies. They appear as a red or blue raised lesion. Typically they begin during the first four weeks of life, grow until about five months of life, and then shrink in size over the next few years.
The table below provides a bit of information about hemangiomas, along with some image examples.
|Phase||Approximate Age||What’s happening?||Examples|
|Growth||Newborn to 14 months (average 8 months)||Hemangioma is growing rapidly (puffing out), and the color is bright red.|
|Resting||8- to 4 months||No change in size, and the skin becomes less shiny|
|1 to 5 years||Lesion shrinks, and the color changes to purple and gray. It may even fade completely|
The cause of hemangioma is currently unknown, but several studies have suggested the importance of estrogen signaling in proliferation. Localized soft-tissue hypoxia coupled with increased circulating estrogen after birth may be the stimulus. Also, a hypothesis was presented by researchers that maternal placenta embolizes to the fetal dermis during gestation, resulting in hemangiomagenesis. However, another group of researchers conducted genetic analyses of single-nucleotide polymorphism in hemangioma tissue compared to the mother’s DNA that contradicted this hypothesis. Other studies have revealed the role of increased angiogenesis and vasculogenesis in the etiology of hemangiomas.
The majority of IHs can be diagnosed by history and physical examination. In rare cases, imaging (ultrasound with Doppler, magnetic resonance imaging), and/or cytology or histopathology are needed to confirm the diagnosis. IHs are usually absent at birth or a small area of pallor, telangiectasias, or duskiness may be seen. A fully formed mass at birth usually indicates a diagnosis other than IH. Superficial hemangiomas in the upper dermis have a bright-red strawberry color, whereas those in the deep dermis and subcutis, deep hemangiomas, may appear blue and be firm or rubbery on palpation. Mixed hemangiomas can have both features. A minimally proliferative IH is an uncommon type that presents with fine macular telangiectasias with an occasional bright-red, papular, proliferative component. Minimally proliferative IHs are more common in the lower body.
A precise history of the growth characteristics of the IH can be very helpful in making the diagnosis. In the first 4 to 8 weeks of life, IHs grow rapidly with primarily volumetric rather than radial growth. This is usually followed by a period of slower growth that can last 6–9 months, with 80% of the growth completed by 3 months. Finally, IHs involute over a period of years. The exceptions to these growth characteristics include minimally proliferative His, which do not substantially proliferate and large, deep IHs in which noticeable growth starts later and lasts longer. If the diagnosis is not clear based on physical examination and growth history (most often in deep hemangiomas with little cutaneous involvement), then either imaging or histopathology can help confirm the diagnosis. On Doppler ultrasound, an IH in the proliferative phase appears as a high-flow, soft-tissue mass usually without direct arteriovenous shunting. On MRI, IHs show a well-circumscribed lesion with intermediate and increased signal intensity on T1- and T2-weighted sequences, respectively, and strong enhancement after gadolinium injections, with fast-flow vessels. Tissue for diagnosis can be obtained via fine-needle aspiration, skin biopsy, or excisional biopsy. Under the microscope, IHs are unencapsulated aggregates of closely packed, thin-walled capillaries, usually with endothelial lining. Blood-filled vessels are separated by scant connective tissue. Their lumina may be thrombosed and organized. Hemosiderin pigment deposition due to vessel rupture may be observed. The GLUT-1 histochemical marker can be helpful in distinguishing IHs from other items on the differential diagnosis, such as vascular malformations.
Most IHs disappear without treatment, leaving minimal to no visible marks. This may take many years, however, and a proportion of lesions may require some form of therapy. Indications for treatment include functional impairment (i.e. visual or feeding compromise), bleeding, potentially life-threatening complications (airway, cardiac, or hepatic disease), and risk of long-term or permanent disfigurement. Large IHs can leave visible skin changes secondary to significant stretching of the skin or alteration of surface texture. When they interfere with vision, breathing, or threaten significant disfigurement (most notably facial lesions, and in particular, nose and lips), they are usually treated.
Medical therapies are most effective when used during the period of most significant hemangioma growth, which corresponds to the first 5 months of life. Ulcerated hemangiomas, a subset of lesions requiring therapy, are usually treated by addressing wound care, pain, and hemangioma growth