Журнал «Здоровье ребенка» 6 (49) 2013

Definition
Vascular anomalies are a heterogeneous group of congenital abnormalities of blood vessels. They are divided into vascular tumors and malformations characterized by a specific structure, pathophysiology, clinical behavior and treatment approaches. Hemangiomas are the most frequent vascular tumor. Lymphatic, capillary, venous and arteriovenous malformations constitute the majority of vascular malformations.

Classification
Currently, to systemize vascular anomalies we use the Classification of the International Society for the Study of vascular anomalies (ISSVA), adopted in 1996 [1]. This classification is based on hemodynamic studies conducted by Mulliken and Glowacki (1982) [2].

The principal issue in this classification is the division of vascular disorders in the vascular tumors and malformations. Hemangioma is an endothelial hyperplasia and a benign tumor. Malformation is a defect of the structure of vessels that occurs as s result of dysfunction in pathways regulating embryogenesis and vasculogenesis.

Due to the appearance in recent year new methods of treatment of the vascular pathology, their management requires a multidisciplinary approach including involvement different specialists: pediatricians, otolaryngologists, dermatologists, hematologists, surgeons, orthopedists, and even psychologists.
 Hemangioma
 Pathophisiology and clinic evolution.

 Infantile hemangioma is the most frequent tumor in children which occurs in about 10% of the population. Recent studies have shown that they are more common in girls with low birth weight who were born before 37 weeks of pregnancy, mainly as a result of in vitro fertilization [3]. Less common congenital hemangiomas are present at birth, with unclear mechanism of formation. Congenital hemangioma can have a quick involution in a relatively short period of time (rapidly involuting congenital hemangioma or RICH), or it can be noninvoluting congenital hemangioma (NICH).

The pathogenesis of infantile hemangioma is still unclear. Currently dominate two theories. The first theory suggests that the source of growing endothelial cells of hemangioma is placental tissue, penetrating into the soft fetal tissue during pregnancy or birth. [4] The second theory suggests that the hemangioma develops from stem cells, which is based on the detection of circulating stem and progenitor cells in patients with hemangiomas [5].

Infantile hemangioma occurs in the first days after birth and presents as a well-limited flat erythematous or bright red spot. At this stage hemangioma can be confused with other vascular anomalies, but the rapid vertical growth of hemangiomas can make a correct diagnosis. Typical clinical presentation is a single node in the form of strawberries, or confluent papules with bright red color (Fig. 1). Brightly colored hemangioma shows intradermal localization of lesion. Hemangiomas with subcutaneous localization do not have the relief and limits lose their regularity. Subcutaneous hemangioma has a bluish tint (Fig. 2). Hemangiomas are often solitary, but the presence of five or more  skin hemangiomas requires further examination in order to rule out the liver vascular anomalies [6].

Usually hemangiomas follow a predictable course with three distinct developmental phases: proliferation (the first week and up to 3 to 6 months of age), quiescence (with 6-8th week to the 12-20th of the month), and involution (6-7 years). Sclerosis is the result of a spontaneous involution of hemangiomas.

Localization on the head and neck in the most of cases corresponds to the innervation of the trigeminal nerve, and localization in projection of the lower branches in 60% of cases is combined with the retropharyngeal hemangioma. Patients with segmental hemangiomas location should be evaluated to rule out syndrome PHACES (malformation of the brain, facial hemangioma, arterial cardiovascular abnormalities, eye pathology, defect sternum) [7].

The diagnosis of a hemangioma is best made by clinical history and physical exam. In cases of unclear diagnosis, the best radiographic modalities to use are either a Doppler ultrasound or MRI.

Management.      

Currently, infantile hemangiomas are divided into two groups, "non problematic" which are small and has non-hazardous location, and "complex" ("problematic"). In regard to "non problematic" hemangiomas justified watchful waiting until the spontaneous regression (involution). Complex hemangiomas are characterized by rapid growth, high volume, specific localization (face, extremities, near the orifices). They also include hemangioma with complications (ulceration, acute inflammation, festering hemangiomas). Management of complex hemangiomas should be active. Different types of distruction and systemic treatment are used. A combination of systemic treatment and destruction is the most promising.  The common systemic treatment is an intravenous or oral administration of corticosteroids with the dose 3-4 mg / kg / day. However, at present a systemic treatment of 1st line is propranolol. In 2008 it was found that the use of non-selective ß-blockers in infants with cardiovascular diseases and infantile hemangioma inhibits proliferation of hemangioma. This observation has been confirmed by multiple studies that have demonstrated the reduction of tumor size 1-2-weeks after the start of treatment with propranolol [8]. The recommended dose of propranolol according to EP and U.S. patent is 2-3 mg / kg / day. The dose is divided into 2-3 administrations over the day.

Propranolol is recommended for the treatment of "problematic" hemangiomas, for whom surgery or watchful waiting is unacceptable. It is the most effective for retropharyngeal, periorbital hemangiomas and other bulk. The mechanism of action of propranolol is not fully understood. It is expected to affect the vascular growth factor and hemodynamic cytokines [9].

However, despite the effectiveness of selective ß-blockers, 50% of hemangiomas required the use of a combination with various kinds of distruction.

The main kinds of destruction include surgical excision, cryosurgery, electro-cautery (including radio frequency coagulation), and laser coagulation.

The principle of selective laser coagulation is selective photothermolysis, described by Anderson and Parrish in 1981[10]. Selective coagulation is used in pulsed dye lasers, generating a wavelength of 585 nm and 595, as well as photosystem. A rapid heating of  vessel to 100 ° C leads to the deterioration ("explosion") of vessel, which manifests by ecchymosis and purpura.

Another type of laser treatment – thermal coagulation, which is achieved by using a long-pulse Nd: YAG laser with a wavelength of 1064 nm. In this case the vessel is slowly warming to 75 ° C, which leads to blood coagulation and the thermal denaturation of the endothelium. Under the high temperature there is a reduction of the vessel and intravascular thrombosis [11].

Malformations.
Vascular malformations are relatively rare and composed of inappropriately connected vasculature. The most common are lymphatic malformation, capillary-venular, venous and arteriovenous. Unlike hemangiomas, vascular malformations never regress.

 Lymphatic malformation consist of extended lymph vessels with defective connection therebetween. The incidence is 1 in 2000-4000 births. Lymphatic malformation classified by size. Lesions are classified as macrocystic (single or multiple cysts> 2 cm3), mikrocystic (<2cm3) and mixed. For lymphatic malformation gradual increase of volume is typical. Lymphatic malformations may be accompanied by swelling and soreness that sets them apart from other vascular malformations. Mikrocystic lymphatic malformations present usually as a soft nodules with normal skin color and transparent contents (Fig. 3). Macrocystic lymphatic malformation sometimes can be quite a large mass of soft tissue and large vesicles with transparent bloody contents. Most lymphatic malformations located in the cervico-fascial area, they can spread into the soft tissues of the mouth and upper respiratory tract, causing dysphagia, speech and swallow disorders.

Management. Surgical excision is commonly used. In the case of difficulties for the surgical approach sclerotherapy can be effectuated. In cases of mikrocystic malformations other methods of distruction as a carbon dioxide laser ablation can be used.      

Capillary malformation. Sporadically occurring vascular pathology (0.3% of newborns), consisting of the extended capillary-channels. May appear on any part of the body, but predominantly observed in the head and neck. Can be placed medially and laterally. The medial capillary malformations are usually lighter with age and disappear, the lateral capillary malformation, or "port wine stains" have a more protracted course. Capillary malformations are present at birth in the form of flat red spots with jagged limits. "Wine spots" are located in the projection of the innervation of the trigeminal nerve. Over time, the formation may progress to the formation of vascular ectasia and through involvement in the deeper-lying vessels, which leads to darkening of the spots and the formation of vascular nodules (Fig. 4). Capillary malformation may exist as isolated pathology and within syndrome. The most common ones are:

•  Sturge-Weberm syndrome, characterized by a combination of capillary malformations in the ophthalmic branch of the trigeminal nerve, leptomeningeal angiomatosis and choroid angioma. Mental retardation and glaucoma can take place;
• Klippel-Trenaunay syndrome (Klippel-Trenaunay), characterized by multiple lymphatic, venous and capillary abnormalities.

Diagnosis is usually made by physical examination alone. MRI may be performed.

Management.

The most effective is the use of laser systems operating on the principle of selective photothermolysis (wavelength - 585, 595 nm). Multiple sessions are needed with the interval 3 weeks to 1 month between treatment procedures. However in few years after the treatment, a partial revascularization may occur, which needs the maintenance treatment.

Venous malformations are malformations of the slow blood flow and occur in approximately 1 in 10,000 newborns. Pathological anastomoses between the veins leads to an expansion of veins, blood clots, further growth of lesion. Venous malformations occur sporadically, but there is evidence of the role of genetic factors in their development. In areas of malformations progesterone receptors have also been found, which may explain the tendency to accelerate the growth of venous malformations during hormonal changes. Clinically, venous malformations are bulky masses mostly localized in the head and neck, which can disrupt the passage of air through the airways up to apnea.

 Management.  

The best results are obtained by the combined therapy with surgical excision, sclerotherapy, laser coagulation with Nd:YAG laser. Recently, systemic therapy with nonselective ß-blockers is used.     

Arteriovenous malformation - a congenital vascular pathology with rapid blood flow. They are often misdiagnosed at birth as other vascular lesions because of the delay in presentation of characteristic signs of the malformation. Puberty and the injury may be triggering factors for the growth of hemangiomas. The diagnosis in most cases is established clinically. On the skin appears bright pink towering formations with clear boundaries, which are characterized by increased local temperature and ripple. The characteristic localization is the central part of the face, mouth, limbs. Growth of malformation is accompanied by local infiltration of soft tissues and their subsequent destruction.

Management.

This pathology is the most difficult to treat. The traditional treatment is intravascular embolization, allowing temporarily control the growth of the malformation, followed by surgical excision. After treatment in 93% of cases revascularization is possible.

Conclusion. Due to the complexity of congenital vascular disease, which can cause not only aesthetic problems but in some cases life-threatening problems, their management requires a multidisciplinary approach including involvement different specialists in order to use all arsenal of current treatment tools.