What are Hemangiomas?

Hemangiomas are childhood masses characterized histologically by high endothelial cell turnover and are characterized by cell markers (GLUT-1, merosin, Lewis Y) that are otherwise found only in human placental tissue and that display phasicity characterized by a rapid proliferative phase, plateau phase, and slow involutional phase. The proper nomenclature for these lesions is infantile hemangioma. Infantile hemangiomas are benign vascular tumors that are not usually present at the time of birth but instead become evident within the first 2 to 3 weeks of life. They are the most common benign tumor of infancy. There is a subgroup of hemangiomas that present fully formed at birth known as congenital hemangiomas. These congenital hemangiomas (as opposed to infantile hemangiomas) do not exhibit the expected accelerated postnatal growth. Some congenital hemangiomas involute rapidly over the first year of life and are called rapidly involuting congenital hemangiomas (RICHs), while some may persist indefinitely without treatment and are called noninvoluting congenital hemangiomas (NICHs).¹

The majority of infantile hemangiomas are localized and, although disconcerting to parents and care providers, are nonthreatenting.² For these lesions, observation and routine monitoring by the pediatrician or dermatologist are acceptable treatment options. A minority of infantile hemangiomas can, however, cause significant morbidity. These require early recognition, timely referral to a specialist, and prompt intervention to minimize complications. Worrisome presentations include multiple hemangiomas and sensitive locations such as beard distribution, periocular, perioral, nasal tip, large regions of the face and neck, and the lumbosacral spine region. In general, larger hemangiomas located on the face are more likely to require treatment. One of the strongest indications for the use of the laser is the presence of ulceration. Other symptoms necessitating therapeutic intervention include congestive heart failure, airway obstruction, dysphagia, infection, failure to thrive, external auditory canal occlusion, visual axis impairment, and severe facial deformity.

Muscular skeletal hemangiomas are not hemangiomas. They are venous malformations that occur in the muscle. With the correct clinical history, a properly performed magnetic resonance imaging examination should be almost pathognomonic. Vertebral body hemangiomas are also not hemangiomas; they are venous malformations that occur in bone. Review of the literature demonstrates numerous studies demonstrating “increased vascularity” of these lesions. However, the increased vascularity is from the venous pooling in the lesion and not from arterial hypertrophy and neovascularity. Liver hemangiomas are not hemangiomas; they are venous malformations that occur in the liver.

Hemangiomas in adults are not hemangiomas; a hemangioma is a childhood-only birthmark. If a vascular birthmark was not present in the childhood stage, then it is not a hemangioma. Hemangiomas are NOT arteriovenous malformations (AVMs), and vice versa. While there is arterial inflow that identifies both these lesions, hemangiomas demonstrate typical tumor vascularity with a central arterial pedicle, and there is fairly minimal, if any, shunting identified in the outflow vessels. An AVM, on the other hand, may have significant venous shunting, with resultant low resistance arterial inflow and arterialized pulsatility in the venous outflow vessels. Venous enlargement is also common in AVMs, resulting from the pressurized shunted arterial flow into the nidus.

Vascular Malformations

Vascular malformations are malformed or dysplastic embryologic spaces that are characterized by normal endothelial cell turnover and abnormal vascular anatomy characterized by the dysplastic vessels involved. All vascular malformations can be placed into one of three groups: low flow, high flow, and combined.

Low-Flow Vascular Malformations—Venous Malformations

Low-flow venous malformations are the most common form of vascular malformation—simplified, they are a number of tortuous vascular channels. They will be evident at birth and will grow with the child. These are common birthmarks present at birth, although they can be clinically occult if deep in location and usually do not become symptomatic until late childhood/early adolescence. Deep subcutaneous or intramuscular venous malformations often manifest with only local swelling and pain. The diagnosis can be difficult because extremity varicosities may be the only visible sign, especially in deep venous malformations. Superficial venous malformations can be seen with bluish-purple skin discoloration. Venous malformations can be divided into truncal and extratruncal lesions. On physical examination, these lesions are soft and easily compressible and will often demonstrate engorgement, especially when the affected extremity is placed in a dependent position. Extratruncal lesions occur from remnants of primitive vessels early in development and are usually dysplastic and diffusely infiltrative. They commonly involve the deep soft tissue structures but patients may have constant pain. Truncal venous malformations occur in differentiated and later-stage vascular structures and patients may have an impressive cutaneous manifestation with limb swelling and varicosities. Diffuse malformations involve multiple areas or regions and are usually part of a syndrome such as Klippel-Trenaunay syndrome. Diagnosis of a venous malformations can usually be made by clinical examination; however, imaging studies such as magnetic resonance imaging (MRI) are performed to evaluate the extent and guide treatment. On MRI, venous malformations are T1 isointense to muscle and T2 hyperintense and demonstrate late enhancement (Fig. 19-1).

Fig 19–1 A 10-year-old boy with focal thigh swelling and pain. Axial T1-weighted (A), T2-weighted (B), and T1-weighted after gadolinium (C) images demonstrating a T1 isointense and T2 hyperintense signal and enhancement after gadolinium in a venous malformation (arrow) in the lateral aspect of left lower extremity.

Treatment of Venous Malformations

Treatment of venous malformations has improved over the past decade as a result of advances in percutaneous and transcatheter embolotherapy and sclerotherapy. Localized and diffuse venous malformations have been treated with sclerotherapy, while some localized lesions may be resected. Sclerotherapy can be performed with ethanol, liquid, and foam detergents. In our practice, we treat venous malformations with ethyl alcohol embolization/sclerotherapy. In many ways it is similar to sclerotherapy performed for lower extremity varicosities, particularly when using agents such as sodium tetradecyl. When dehydrated ethyl alcohol is used, however, the potential for serious complications is increased by an order of magnitude. Local ethanol complications are related to the transmural necrosis of the agent and spread to the surrounding tissues.

Preprocedure evaluation of a malformation with either ultrasound or MRI is helpful not only in defining the extent of the abnormality but also in aiding to determine possible direct access into the lesion (Figs. 19-2 and 19-3). Access into the malformation is usually performed with ultrasound and fluoroscopic guidance (Fig. 19-4). Biplane fluoroscopy can be used if the location of the lesion allows. Direct comparison with the MR images can also be very helpful. Proper positioning on the angiographic table is critical to successfully access the malformation and to allow proper anesthesia monitoring. All alcohol embolization procedures are performed with the patient under general anesthesia to allow for proper sedation and pain management as well as to prepare should complications of treatment (such as cardiovascular collapse) occur. Additionally, a tourniquet for control with a calibrated cuff can be used if the location of the lesions allows. When using a tourniquet, we do not exceed diastolic blood pressure and often only use minimal pressures in the 20 to 40 mm Hg range.

Fig 19–2 Ultrasound Doppler examination demonstrates a heterogeneous lesion with no increased flow consistent with a low-flow vascular venous malformation.

Fig 19–3 Coronal fat-saturated T1-weighted image. After the addition of gadolinium, enhancement of the dysplastic draining vein is demonstrated (arrow).

Fig 19–4 Initial venogram with dilute contrast.

The technique for the alcohol administration has evolved over the past 10 years. Previously, dehydrated ethanol was opacified with a small amount of ethiodized oil (Ethiodol) to increase the visualization of the administered alcohol under fluoroscopic control. Currently, we use a negative contrast technique. This consists of opacification of the malformation with contrast followed by administration of the ethyl alcohol that replaces the contrast on live fluoroscopic evaluation (Fig. 19-5). Once we have either treated the entire lesion or reached our sclerosant limits, the procedure is concluded (Fig. 19-6). The absolute maximum for ethyl alcohol is 1 mL/kg. In our practice, we rarely exceed 0.5 mL/kg in one procedure. A good working dose limit for ethyl alcohol is 0.25 mg/kg for the entire case. We also limit our total injected volume to 0.1 mL/kg/injection and allow at least 5 minutes between alcohol administrations. By adhering to these recommendations, we have completed safe treatment for many patients without the use of pulmonary arterial catheter monitoring.

Fig 19–5 Direct puncture venography using a small angiocatheter.

Fig 19–6 Posttreatment scout film demonstrating two separate treatment punctures.

Occasionally, a lesion can be treated in one session; however, most require several (two to four) treatments to reach our clinical endpoint of treating the pain associated with a symptomatic malformation. We do not treat asymptomatic lesions unless there is a significant cosmetic issue, which can occur with lesions on the face and neck. Treatments are usually spaced apart by 3 to 4 months to allow for postprocedural edema to resolve.

Our standard postprocedure orders include intravenous ketorolac, dexamethasone, and antibiotic coverage for the first 24 hours of treatment. Following overnight observation, patients are discharged home with an outpatient oral medication regimen of a methylprednisolone dose pack, ibuprofen therapy, and oral antibiotics.

Evaluation of the venous drainage of venous malformations is essential in their treatment. Malformations with no or limited venous drainage can be treated with embolic agents with higher effectiveness and less risk than malformations with normal draining vessels, while lesions with drainage into dysplastic veins or a venous ectasia can be most problematic to treat. Venous malformations may have a number of large-diameter connections to the deep venous system. It is important to control the injection to prevent the liquid embolics from entering these central veins. Burrows et al. have reported good result in 75% to 90% of their patient cohort treated with serial alcohol administration. However, many patients have chronic pain symptoms, and their clinical improvement may lag significantly behind a more technically successful treatment.