Pathophysiology of Telangiectasias

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CHAPTER 4 Pathophysiology of Telangiectasias

The term telangiectasia was first coined in 1807 by Von Graf to describe a superficial vessel of the skin visible to the human eye.1 These vessels measure 0.1 to 1 mm in diameter and represent an expanded venule, capillary or arteriole. Telangiectasias that originate from arterioles on the arterial side of a capillary loop tend to be small and bright red and do not protrude above the skin surface. Telangiectasias that originate from venules on the venous side of a capillary loop are blue, wider, and often protrude above the skin surface. Sometimes, telangiectasias, especially those arising at the capillary loop, are red at first but with time become blue, probably due to increasing hydrostatic pressure and backflow from deep veins.2,3

Classification

Redisch and Pelzer4 classified telangiectasias into four types based upon clinical appearance (Fig. 4.1):

image

Figure 4.1 Four types of telangiectasias. A, Simple. B, Arborized. C, Spider. D, Papular.

(Adapted from Reddish W, Peltzer RH: Am Heart J 37:106, 1949.)

Papular telangiectasias are frequently present in patients with collagen vascular disease. Spider telangiectasias are red and arise from a central filling vessel of arteriolar origin. Red linear telangiectasias occur on the face (especially the nose) or legs. Blue linear or anastomosing telangiectasias are found most often on the legs.

Raymond-Martimbeau and Dupuis3 have proposed another classification based on the relationship between telangiectasias and superficial as well as deep veins. Using duplex ultrasound, they evaluated 525 consecutive patients with 884 zones of telangiectasia without underlying saphenous or perforator vein incompetence. They found that 8.8% of the telangiectasias joined the deep venous system, 12.6% joined the superficial venous system, 71.2% were directly connected to reticular veins and 7.4% had no obvious connection. This is in contradistinction to the reports of very high incidence of arterial venous anastomoses for leg telangiectasias.5

The actual etiology of telangiectasias may be identical to that of varicose veins.6 However, the findings of Raymond-Martimbeau and Dupuis suggest that valvular damage occurs with subsequent venous hypertension that is transmitted to epidermal vessels, which then elongate and dilate. Our research has implicated a leukocyte–endothelial interaction that relates intercellular adhesion molecule-1 and monocytes to adherence and migration of cells.7 Valve and vein wall damage is produced by monocytes in the interstitial tissue.8 Thus, pharmacologic treatment of telangiectasias may be possible in the future.

This Chapter discusses the pathophysiology and anatomy of telangiectasias occurring on the lower extremities.

Patterns

Two common patterns of telangiectasias on the legs of women, besides red or blue streaks, are the parallel linear pattern, usually found on the medial thigh (Fig. 4.2), and the arborizing or radiating cartwheel pattern, seen most often on the lateral thigh (Fig. 4.3).9 These two subsets of telangiectasias seem to run in families and may form anastomosing complexes as large as 15 cm in diameter. The arborizing type on the lateral thigh usually appears with ‘feeding’ reticular veins (see Fig. 1.11). These complexes have been termed venous stars, sunburst venous blemishes and spider leg veins by various authors.

Pathogenesis

The pathogenesis of each type of telangiectasia is somewhat different. Multiple factors may play a role in the development of new blood vessels or the dilation of existing blood vessels (see Chapters 2 and 8). Acquired telangiectasias probably result from the release or activation of vasoactive substances, such as hormones and other chemicals. Conditions associated with increased or activated vasoactive substances include anoxia, infection and certain physical factors that results in capillary or venular neogenesis.4,10,11 One common area for the development of telangiectasia is the medial thigh. This has been thought to be, in part, a result of pressure exerted by crossing the legs. A report on tissue atrophy in a woman with associated telangiectasia at the site of pressure where her legs crossed suggests that intermittent pressure results in subcutaneous tissue loss or atrophy.12 Unfortunately, to our knowledge, no formal studies on tissue pressure have been performed. Box 4.1, an extension of observations made by Shelley13 as well as Anderson and Smith,14 lists the major etiologies associated with telangiectasias arising on the lower extremities.

Incidence

The incidence of varicose and telangiectatic leg veins in the general population is presented in Chapter 2. The relationship between varicose veins and spider leg veins (telangiectasias) is profound. The anatomy and pathophysiology of telangiectasia is presented in Chapters 1 and 3. Telangiectasias increase in incidence with advancing age.15 Among neonates, the prevalence of telangiectasias is 3.8%, with 26% occurring on the legs.16

Two surveys have detailed the characteristics of patients seeking treatment of unwanted spider leg veins. Duffy,17 in a nonrandomized survey of his patients, reported a 90% family history of varicose or telangiectatic leg veins. Patients included three sets of identical twins with similar appearing leg telangiectasias. Sadick,18 in a nonrandomized survey of 100 patients seeking treatment, found a 43% family history of varicose or telangiectatic leg veins. Both surveys found that one third of the patients first noted the development of these veins during pregnancy. Among this subset of patients, veins became most severe after the third pregnancy.17 Between 20% and 30% of patients developed these veins before pregnancy, and 18% of women noted the onset of the veins while taking oral contraceptives. Both authors concluded that the development of leg telangiectasia is probably a partially sex-linked, autosomal dominant condition with incomplete penetrance and variable expressivity.

Pathophysiology

Multiple conditions – inherited, acquired, as well as iatrogenic – are involved in telangiectasia formation.

Genetic/congenital factors

Numerous genetic or congenital conditions (listed in Box 4.1) display cutaneous telangiectasia. The pathogenesis for the development of telangiectasia in these syndromes is unknown. Genetic syndromes associated with leg telangiectasias include nevus flammeus (alone or as a component of Klippel–Trénaunay syndrome (KTS)), nevus araneus, angioma serpiginosum, Bockenheimer’s syndrome (diffuse genuine phlebectasia), congenital neuroangiopathies (especially Maffucci’s syndrome), congenital poikiloderma, essential progressive or generalized telangiectasia, cutis marmorata telangiectatica congenita, and diffuse neonatal hemangiomatosis.

Nevus flammeus

Nevi flammei (port-wine stains) affect 0.3% to 1% of the population,19,20 with women being twice as likely to be affected as men.21,22 Cases are usually sporadic, but a 10% familial incidence21 and an autosomal dominant inheritance have been described.2326 Lesions occur in various shapes and sizes on any part of the body. They most commonly occur on the face but may cover large areas of the body, including an entire arm, leg, or trunk (Fig. 4.4). Lesions often overlay the distribution of peripheral nerves. Nevi flammei are usually macular and vary in color depending upon the extent and depth of vascular involvement. Lesions become progressively nodular and darker with time and may ulcerate and bleed from minor trauma.

Histologic examination shows a collection of thin-walled capillary and cavernous vessels arranged loosely throughout the superficial and deep dermis (Fig. 4.5). These vessels represent dilations of postcapillary venules within the superficial dermis, with a mean depth of 0.46 mm.27 In infancy, histopathologic changes of cutaneous vasculature are minimal. With advancing age, however, these lesions usually undergo progressive ectasia and erythrocyte stasis.27 Although rare, cavernous hemangiomas arising from arteriovenous malformations may occur within the lesions.28 There may also be evidence of other vascular malformations or neovascularization.27 Further, some lesions on the legs may be associated with prominent telangiectasias and reticular varicose veins (Fig. 4.6).

A nevus flammeus can also be a component of a larger congenital vascular disease; the most common that involves the leg being KTS.

Klippel–Trénaunay syndrome

With KTS (Fig. 4.7), the cutaneous vascular abnormality is associated with underlying varicose and telangiectatic veins with or without significant abnormalities of the deep and superficial system or arteriovenous anastomoses. In addition, hypertrophy of soft tissue and bone may occur with overgrowth of the involved extremity (Figs 4.8 and 4.9).

image

Figure 4.8 Venogram film of the right calf (anteroposterior projection) of the patient shown in Figure 4.7. There are multiple dilated collateral dermal venules and a grossly enlarged lateral accessory saphenous vein along the posterolateral aspect of the calf, which is avalvular. The deep venous system is absent.

(Courtesy Christopher Sebrechts MD)

image

Figure 4.9 Magnetic resonance image, coronal T1-weighted, of the calves (TR 500, TE 20) of the patient in Figure 4.7. Multiple small collateral vessels in the subcutaneous fat of the right calf are shown as a spaghetti-like accumulation of dermal venulectases. Note the enlarged lateral accessory vein present along the posterolateral aspect of the right calf.

The cause of KTS is unknown. Its prevalence in newborns is estimated to be 1 : 25,000.29 There is no uniformly apparent hereditary factor.30 One study of 14 affected patients suggests an autosomal dominant inheritance,31 but some authors speculate that an atresia, agenesis or compression of the deep venous system by fibrotic tissue is the cause.32 Other authors suggest that a congenital weakness of the venous wall, in combination with vascular hypertension from an abnormal venous system, leads to the development of KTS.33 Baskerville et al34 studied 49 patients with KTS and found that 68% had a superficial, embryologic venous channel on the lateral aspect of the thigh (Fig. 4.10). Histologic and venous flow studies suggest that, because these veins are usually present at birth and avalvular, KTS is caused by a mesodermal abnormality during fetal development that leads to persistence of arteriovenous communications, causing the triad of a nevus flammeus, soft tissue hypertrophy and varicosities.35 This entire patient; population had clinical varicose veins, and 88% had pain and limb swelling. Twenty-two percent had severe hemorrhage from varicose vein rupture and 6% had a history of superficial thrombophlebitis. Baskerville et al34 recommended surgical excision-avulsion of symptomatic superficial varices, with Villavicencio,36 building upon his experience with 14 patients; also recommending surgical excision followed by sclerotherapy to treat patients with intractable symptoms.

Servelle37 presented his findings on 786 patients with KTS. He found venographic evidence for obstruction in most patients and postulated that changes seen in KTS are manifestations of this obstruction. In addition to cutaneous and soft tissue findings, Servelle noted a 36% incidence of varicose veins in his patient population. Concomitant malformations of the deep venous system (avalvulia, aneurysmata, aplasia, lateral marginal veins) have been found in up to 94% of patients.38 Servelle recommended surgical intervention to the deep venous system and cautioned against treating superficial varicosities, owing to the potential for increased outflow obstruction.

When associated with KTS, cutaneous telangiectasias, venulectasias and varicose veins occur in the distribution of the underlying vascular malformation of soft tissue and bone. Some patients have a persistent embryologic lateral limb bud vein. The large drainage capacity of this vein may limit venous hypertension. In this instance, microcirculatory change, rather than large vessel change, may account for limb hypertrophy.39 Thus, because KTS can be composed of a variable venous system, sclerotherapy treatment must be performed only after a thorough vascular evaluation.40 Extensive pure venous malformations without other sequelae have also been reported and are distinct from KTS.41 These lesions represent dilated venous tumors involving both skin and muscle. Coagulation studies are abnormal in 88% of patients.

Most venous angiodysplasias demonstrate associated telangiectasias (Figs 4.11 and 4.12).

Proteus syndrome is a congenital hamartomatous condition that may have overlapping features with KTS.42 In 1983, Wiedemann et al43 described Proteus syndrome as consisting of partial gigantism of the hands or feet, hemihypertrophy, pigmented nevi, soft tissue tumors, macrocephaly and other hamartomatous changes. Patients with Proteus syndrome can also demonstrate prominent capillary hemangiomas, telangiectasia, and varicosities.4447 Clinical findings are usually evident at or shortly after birth. This condition may represent a somatic mutation that influences the local regulation or production of tissue growth factors.48

Sclerotherapy to nontruncal varicose and telangiectatic veins can restore some degree of venous competency and relieve symptoms. In addition to experiencing a heavy, tired feeling of the affected limb, patients may have recurrent bleeding from cutaneous vascular blebs. These vessels are easily traumatized, with trauma occasionally leading to cutaneous and soft tissue infections. Sclerosing these vessels is helpful and has been practiced for more than 60 years.49

A complete discussion of the surgical management of KTS or the vascular component of Proteus syndrome is beyond the scope of this text. But, in short, if an incompetent feeding varicose vein is found alone with an intact deep venous system, the former can be avulsed safely. This procedure is often combined with sclerotherapy to distal varices. Foam sclerotherapy can be an important treatment modality, although dozens of treatment sessions may be required to minimize the volume of injected foam. Care must be taken to ensure adequate venous return from the remaining vessels. Treating perforating veins is usually quite difficult because there may be hundreds of connections between the superficial and deep venous systems.40

Laser coagulation or photocoagulation is reserved for cutaneous ectasia, which usually occurs within the nevus flammeus. These manifestations are not treated for cosmetic reasons but to prevent bleeding and infection (Fig. 4.13) (see Chapter 13).

image

Figure 4.13 A, Before, and B after, treatment of a section of the nevus flammeus and associated superficial varicosity of the patient shown in Figure 4.6. The reticular veins were treated with polidocanol 0.75% (6 ml total) followed by multiple impacts with the Candela SPTL-I pulsed-dye laser at 8 J/cm2. C, Clinical appearance 5 years after last sclerotherapy/laser treatment. Note the recurrence of venules and vascular ectasia.

Nevus araneus

Nevi aranei (spider telangiectasias) may occur as a component of a number of congenital and acquired diseases. They are found in up to 15% of the normal population and increase in number during pregnancy, liver disease and multiple other conditions.50 Ninety-nine percent of nevi aranei occur superior to the umbilicus.50,51

Lesions appear as bright red macules composed of a central red dot, with fine blood vessels radiating from the center (Fig. 4.14). The central vessel may pulsate, indicating its arteriolar origin. Point compression of the central dot blanches the radiating vessels. One genetic disease with this form of telangiectasia is ataxia telangiectasia, which may have lesions distributed within the popliteal fossae.52,53

Vascular spiders arise from the terminal arteriole (see Fig. 4.14).4 Within the spider telangiectasia, blood pressure is lower than systolic pressure but higher than venous pressure. One measurement demonstrated its pressure to be 85 mmHg when systolic pressure was 120 mmHg.54 The vessels arise within the deep dermis and push their way up into the superficial dermis as a space-occupying lesion. The central arteriole connects to dilated venous saccules with radiating venous legs in the papillary dermis.50 Detailed histologic studies have provided little understanding of the factors responsible for the initial growth of nevi aranei.55

Because spider telangiectasias are composed of a central arteriole, sclerotherapy as treatment usually produces ulcerations (see Chapter 8). Therefore, recommended treatment involves fibrosing the central feeding arteriole via the pulsed-dye laser (PDL) at 585 nm or 595 nm, continuous wave lasers at 511 nm to 577 nm, intense pulsed light (IPL), or electrodesiccation (see Chapter 12).

Angioma serpiginosum

Angioma serpiginosum is a rare nevoid disorder of the upper dermal vasculature. The disease usually occurs on the lower extremities in women and has its onset in childhood. Although most cases are sporadic, one family study suggests an autosomal dominant inheritance.56 Lesions appear as small erythematous puncta, which occur in groups. The lesions enlarge as new puncta form at the periphery, while those in the center fade. This results in a reticular or serpiginous pattern. A dilation of the subpapillary venous plexus may lead to telangiectasias. Histologic examination shows a number of ectatic capillaries in the superficial dermis. Endothelial cells are vacuolate, appear hyperplastic and have an increased number of interendothelial junctions. Capillary walls are thickened with prominant basal laminae and a ‘heavy’ precipitation of fine fibrillar material. The deeper dermis is unremarkable.57 Therefore, angioma serpiginosum may represent a type of capillary nevus.

Bockenheimer’s syndrome (diffuse genuine phlebectasia)

Diffuse genuine phlebectasia was first described by Bockenheimer58 in 1907. One review has documented 40 cases in the literature.59 This rare syndrome represents a deep venous malformation that is rarely present at birth, usually first manifesting in childhood. Multiple large venous sinusoids or cavernous hemangiomas develop, usually on an extremity. These frequently thrombose, hemorrhage, ulcerate and may ultimately progress to a gangrenous infection. Unilateral localization is common. Secondary cutaneous telangiectasia develops in response to venous hypertension. Late manifestations are soft tissue and/or bone hypotrophy or hypertrophy.

Compression therapy is generally beneficial to prevent manifestations of both venous hypertension as well as thromboses. Surgical excision and phlebectomy have produced varying results, generally with recurrence.60,61 Sclerotherapy has been successful in one of two cases.62,63

Congenital poikiloderma

Congenital poikiloderma (Rothmund–Thomson syndrome) is a rare neurocutaneous syndrome that has its onset in the first year of life. There appears to be a female predominance. Although an autosomal dominant inheritance pattern has been demonstrated, 70% of cases show a familial recessive inheritance.68 A fine telangiectatic network first appears on the cheeks and progresses within a year to involve the head, arms, buttocks and legs. There may be associated scaling of the skin and lichenoid papules. Affected patients often have sparse hair, as well as soft and translucent skin. Dwarfism, cataracts, dental abnormalities, mental retardation, hypogenitalism and diabetes mellitus may also occur.68

Essential progressive telangiectasia

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