Vascular Malformations

Vascular Malformations
These come in a myriad of forms and can affect any part of the body,  They can involve just veins or they can involve veins and arteries.  A full assessment by a phlebologist or vascular surgeon is required before embarking on treatment which is typically a multi disciplinary approach.  The most common treatment for such malformations is either vascular lasers or sclerotherapy using sodium tetradecyl sulphate or ethanol.

Vascular malformations are subdivided into low-flow (capillary, venous, lymphatic, or a combination) and high-flow (arterial) anomalies. Clinical, histological, histochemical, and biochemical differences and radiographic imaging findings support this classification. The prevalence at birth of capillary malformations is reported at 0.3% equal in both sexes.

Capillary Malformations
Capillary malformations were once referred to as port-wine stains; this term is now outdated. Genetic studies have mapped capillary malformations to chromosome 5q14-21, showing a defect in the RASA1 gene. The RASA1 gene encodes p120 Ras GTPase-activating protein. When mutated, p120 Ras GTPase-activating protein binds to Krev-1/rap1a, an integrin β1–mediated cell adhesion and angiogenesis protein. The cause of capillary malformations is not understood.

Capillary malformations are the most common cutaneous vascular malformation appearing as a macular stain. Capillary malformations are represented by ectatic capillaries and medium-sized venules with thin walls and flat endothelial cells. The lack of sympathetic innervation regulating blood flow in vessels with capillary malformation is believed to produce progressive ectasia. Consequently, a characteristic red and purple lesion is seen upon examination. 

Unlike hemangiomas, capillary malformations do not undergo spontaneous involution. Further, the endothelium does not exhibit hyper-proliferation but has a normal turnover rate. In a study of 415 patients with capillary malformations in the fifth decade of life, Geronemus and Ashinoff found hypertrophy, nodules, or both in 65% of the capillary vasculature. In addition to these features, bridged fenestrations can be seen by scanning electron microscopy. These are normally found in venous capillaries surrounding sweat glands and hair follicles and represent areas of accelerated exchange between circulation and surrounding tissue.

Clinical
Patient history and physical examination findings are important in order to correctly classify malformations. Appropriate treatment begins with the correct diagnosis. 

The general consensus is that capillary malformations are located in the dermis (deeper layer of the skin). They present as well-defined patches of red or purple skin discoloration at birth but may be masked by the normal redness (erythema) of neonatal skin. Their growth continues with the person’s age, becoming increasingly nodular and covering larger areas with time.

Although capillary malformations can occur anywhere on the body, they are most commonly seen on the face. When capillary malformations occur on the face, they normally have a dermatomal distribution (follow the distribution of nerves). Fifty-five percent of facial capillary malformations overlap sensory dermatomes, occur on both sides, or cross the mid line. The remaining 45% occur in one of the three trigeminal dermatomes. Maxillary or mandibular overgrowth with labial hypertrophy and gingival hyperplasia may be seen in the lower and mid face. Soft tissue and skeletal overgrowth may also be seen in cutaneous capillary malformations of the trunk and limbs.

Capillary malformations are commonly associated with developmental defects. For example, a capillary malformation on the posterior chest may be indicative of an underlying arteriovenous malformation (AVM) of the spinal cord (Cobb syndrome), or an occipital capillary malformation may overlie an encephalocele. Spinal dysraphism, lipomeningocele, tethered spinal cord, and diastematomyelia may be present when the capillary malformation overlies the cervical or lumbosacral spine. In these cases, careful neurologic examination, radiographic examination, spinal radiographic imaging, and bladder function studies are indicated because subtle signs of neurogenic bladder dysfunction or lower extremity weakness may be present. 

Imaging Studies
Magnetic resonance angiography can be used to help document the presence or absence of enlarged vessels in vascular anomalies based on the presence of gradient recall echo sequences. Confirm the diagnosis with appropriate clinical history and physical examination findings.

Magnetic resonance imaging findings may serve as a guide for planned surgical excision.

Doppler studies can be used to evaluate the flow pattern of the lesion. Arterial malformations demonstrate high flow; this is a noninvasive method of differentiating them from capillary malformations.

Medical Treatment
Reassure patients with asymptomatic lesions that the lesion is benign. Uncommonly, capillary malformations bleed after minor trauma, and the bleeding may be difficult to stop. Compression of the area and immediate medical assistance is necessary. More complex syndromes may require assessment by a team of specialists including pediatricians, radiologists, dermatologists, phlebologists and plastic surgeons.

Some vascular malformations will respond to sclerotherapy with sodium tetradecyl sulphate, polidocanol or ethanol.

Surgical Treatment
The current treatment of choice for capillary vascular malformations is vascular lasers or IPL although only 15-20% of lesions clear completely. Capillary malformations located on the medial part of the cheek, upper cutaneous lip and nose, and the V2 dermatome respond poorly. The areas that respond best to treatment include lesions in the periorbital region, the neck, and the temple. End results may be due to differences in adnexa, fibrous proteins, density of vessels, and nerves. 

Excision is useful for small fibrovascular nodules, but patients with extensive fibronodular hypertrophy may require resection and resurfacing with split- or full-thickness skin grafts. 

When mandibular prognathism or occlusal canting from hemimaxillary vertical overgrowth occurs, orthognathic procedures are indicated.

Follow Up

Provide monthly follow-up care to neonates with birthmarks. Hemangiomas begin proliferating within the first month, while capillary malformations enlarge commensurately with the child’s growth. Invasion of important anatomic structures, cosmetic deformity, pain, and swelling may prompt surgical treatment. Monitor patients for recurrence after lesions are resected.

Classification of vascular malformations remains controversial. New findings by Breugem et al suggest that the pathologic abnormalities of capillary malformations appear to be located in postcapillary venules rather than the capillaries themselves. Thus, port-wine stains may need to be redefined from their original classification under capillary malformations.

Future advancements in the treatment of capillary malformations include improved selective laser ablation and gene therapy. However, gene therapy remains experimental, with target cells still being evaluated.

Klippel-Trenaunay-Weber syndrome
Klippel-Trenaunay-Weber syndrome is often associated with the triad of capillary malformations, venous malformations or varicose veins, and hypertrophy of affected tissues. Vascular abnormalities lead to muscle hypertrophy and thickening of the skin, subcutaneous tissues, and bone. Although port-wine stains commonly occur cutaneously, venous and lymphatic malformations are common in the limbs. Most often, they affect a single lower extremity. A persistent lateral vein extending from the lateral malleolus to the gluteal region is common.

Parkes Weber syndrome
Parkes Weber syndrome is the combination of a capillary malformation and an AVM. It is commonly large and pink, with the affected limb being longer and warmer than the contralateral limb.

Hyperkeratotic cutaneous capillary-venous malformation
The hyperkeratotic cutaneous capillary-venous malformation is normally associated with vascular malformation of the brain and affects the tissue around the eye. It is an autosomal dominant abnormality due to a mutation in the KRIT1 gene.

Sturge-Weber syndrome
Sturge-Weber syndrome is a capillary malformation in the distribution of the ophthalmic and maxillary divisions of the trigeminal nerve of the face. This vascular malformation may be associated with many other symptoms, such as jacksonian seizures, mental retardation, calcification of the leptomeninges, glaucoma, and contralateral hemiplegia.

Campbell de Morgan spots 
These are red round spots which can appear on the face or any part of the body and are treated with laser.