Hrev_master Veins and Lymphatics 2014; volume 3:4050 [page 64] [Veins and Lymphatics 2014; 3:4050] Marginal vein is not a varicose vein; it is a venous malformation Byung-Boong Lee Center for the Lymphedema and Vascular Malformations, George Washington University, Washington DC; Uniformed Services University of the Health Sciences, Bethesda, MD, USA Abstract Marginal vein (MV) is one form of venous malformation (VM); MV is not a varicose vein. MV is the outcome of defective development during the later stage of embryogenesis while the vein trunk is formed. It is an embryonic vein tissue remnant remaining on birth follow- ing the failure of normal involutional process. MV is the most common VM involved to Klippel-Trenaunay syndrome (KTS); together with the lymphatic malformation, MV is one of two clinically most important congenital vascu- lar malformation components among KTS. MV causes chronic venous insufficiency (CVI) due to a unique condition of avalvulosis (lack of venous valve development) it accompanies with. Besides, it accompanies a high risk of venous thromboembolism (VTE) due to its structural defect with a lack of smooth muscle cell to form the media properly as a truncular VM infrequently causing fatal pulmonary embolism. Therefore, the MV is indicated for the surgical excision whenever feasible not only for the prevention of VTE and CVI but also for abnormal long bone growth known as vas- cular bone syndrome as well as lymphatic com- plication precipitated by MV. Introduction Marginal vein (MV)1-4 is often mistakenly considered as a varicose vein since most of MV locates very superficially beneath the skin with a minimum soft tissue coverage although it runs on the lateral aspect of the lower extrem- ity, which is odd/unusual location for common varicose veins. MV is not a matured vein like varicose veins (of superficial vein system); vein; it is an embryonic vein remnant follow- ing the failure of normal involutional process through the maturation period of vein trunk formation and remains after the birth. Although MV looks like ordinary varicose vein of saphenous/superficial vein especially when it is located in superficially, MV is a lot more clinically serious not only to cause severe chronic venous insufficiency (CVI) but also constant source of intravascular coagulation resulting in venous thrombo-embolism (VTE) (Figure 1). MV is one of venous malformations (VMs);5-8 VM is a common form of congenital vascular malformations (CVMs)9-12 and the MV is one form of truncular VMs as the outcome of defective development during the later stage of embryogenesis while the vascular/venous trunk is formed. The extent and severity of the MV are variable depending upon the degree of defective development along the last/truncular stage of embryogenesis while forming the vein trunk so that all the MVs present in different lengths as well as different locations; they are also named differently from lateral embryonic vein to sciatic vein.3,13-15 However, all these lat- erally located embryonic veins have same defective condition of the vein wall with insuf- ficient smooth muscle layers development (cf. varicose vein). Besides, as a part of defective development of the venous wall, they accompa- ny a unique condition of the lack of normal venous valves development known as avalvu- losis. The MV has a unique clinical signifi- cance as the most common form of VM involved to Klippel-Trenaunay syndrome (KTS).16-19 KTS is a well known name-based eponym representing a clinical condition of various congenital anomalies affecting not only the vascular system but also the soft tis- sue as well as the skeletal system. The MV/lat- eral embryonic vein as a truncular VM lesion1-4,20,21 is potentially most dangerous CVM lesion among various vascular malformation compo- nents involved to the KTS; together with less common extratruncular VM, MV as a truncular VM belongs to the CVM components of KTS. Together with this VM group,22-25 the lym- phatic malformation (LM) group26-29 affects the clinical condition of the KTS as second most serious CVM components, directly and indi- rectly in various degrees together with capil- lary malformation (CM);30,31 LM presents in the majority as a truncular lesion known as primary lymphedema and/or extratruncular lesion known as lymphangioma among KTS. These two, VM and LM, combined form of CVMs are classified as hemolymphatic malfor- mation (HLM) by modified Hamburg Classification in view of inseparable impact on overall hemodynamic status32-35 (Tables 1 and 2). Nevertheless, such complicated condition of the MV, often combined with other CVMs (e.g. deep vein aplasia/hypoplasia) has been often neglected as a relatively benign condi- tion although the chronic venous hypertension generated by the unique condition of avalvulo- sis - lack of venous valve - will give a profound impact on the CVI. Lately, MV was found to generate much more serious condition to cause the VTE. When this MV is combined with a unique con- dition of coagulopathy, which is common among the extratruncular VM lesions, it infre- quently becomes a source of serious, even fatal, pulmonary embolism (PE) as well.36-39 Therefore, proper understanding on the MV is warranted for all the phlebologists who will have more chance to encounter such unique condition mimicking innocuous varicose veins than other clinical specialists. Definition The MV is one of the VMs, and VM is one of the CVMs affecting the venous system alone.9-12 CVM represents a whole group of birth defects caused by the developmental arrest during the embryogenesis to form the vascular system: artery, vein, and lymphatics. Depending upon the embryological stage when the defective development occurs, its clinical behavior is affected profoundly by unique embryological characteristics originated from the mesenchymal cells/angioblasts.40-43 Therefore, all these inborn vascular defects exist already at birth and the embryonic tissue remnant originated from the defective devel- opment in its early stage continues to grow at a rate that is proportional to the growth rate of the body (cf. hemangioma); this unique group originated from the early stage is further defined/sub-classified to the extratruncular type to differentiate from truncular type which represents other group of defective develop- ment originated from the late stage. The extra- truncular lesions remain as a cluster of mal- formed vessels since defective development Correspondence: Byung-Boong (B.B.) Lee, Center for Vein, Lymphatics and Vascular Malformation, George Washington University School of Medicine, Washington, DC, USA. Division of Vascular Surgery, Department of Surgery, George Washington University Medical Center, 22nd and I Street, NW, 6th Floor, Washington, DC 20037 USA. E-mail: bblee38@comcast.net Key words: marginal vein, venous malformation, lymphatic malformation, Klippel-Trenaunay syn- drome, venous thromboembolism, vascular bone syndrome. Received for publication: 12 May 2014. Revision received: 4 July 2014. Accepted for publication: 7 July 2014. This work is licensed under a Creative Commons Attribution 3.0 License (by-nc 3.0). ©Copyright B.-B. Lee, 2014 Licensee PAGEPress, Italy Veins and Lymphatics 2014; 3:4050 doi:10.4081/vl.2014.4050 No n c om me rci al us e o nly Review [Veins and Lymphatics 2014; 3:4050] [page 65] occurred while the vascular structure is still in primitive reticular network. This CVM group is classified together with the vascular tumor group under the category of the vascular anomaly; the most of vascular tumor is represented by (neonatal or infantile) hemangioma.44-47 CVM and vascular tumor/ hemangioma represent entire anomalous vas- cular structures together but both groups are totally different not only its etio-pathogenesis but also its clinical behavior.48 The Hamburg Classification32-35 has a unique value to provide not only different embryological characteristics of the CVMs from different embryonic stages but also its anatomical, histological, patho-physiological, and hemodynamic status for accurate diagno- sis to improve its clinical management. The Hamburg Classification defined the CVMs to six groups based on the vascular systems involved: arterial,49,50 venous,51-54 arterio- venous (AVM),55-58 LM,59-62 capillary,30,31 and combined vascular malformations.63-65 When LM66-68 is mixed/co-exists with VM or AVM69-71 as a combined form of the CVM, they were named to HLM21,65,72 (Table 1). Based on Hamburg Classification, each CVM is further sub-classified to two different groups in order to verify unique embryological characteristics certain CVM groups possess: Extratruncular and Truncular lesions based on the embryological stage when developmental arrest has occurred32-35 (Table 2). The extratruncular lesions represent the defective development occurred in the earlier stage of embryonic life retaining the mes- enchymal cells (angioblasts) characteristics of mesodermal origin. Therefore, they possess evolutional potential to grow when stimulated internally (e.g. menarche, pregnancy, and hor- mone) or externally (e.g. trauma, surgery).40-43 On contrary, the truncular lesions no longer possess this embryonic characteristics of the mesenchymal cells since they represent the defective development during the later stage of the embryonic development during the vascu- lar trunk formation period.40-43 However, trun- cular lesions cause more serious hemodynam- ic consequences related to the type of CVM (e.g. marginal veins) despite minimal risk of recurrence Therefore, an extreme variety of the clinical behavior of the CVM lesions is heavily influ- enced by unique embryological characteristics of different stages of embryogenesis. Accordingly, CVM lesions are known as an enigma of modern medicine with a wide range of clinical presentations, unpredictable clinical course, and erratic response to treatment with the potential for high rates of recurrence.73-76 Extratruncular VM lesions never involve the main trunk of formed vein itself but remain as an independent lesion from the named/matured vein since they are pre-truncal embryonic lesions occurred before the main vascular trunks are formed. Therefore, they represent clinically either as diffuse, infiltrat- ing lesions or localized, limited lesions. But the majority of truncular lesions are directly involved to the vein trunks since the defective development occurs along the late stage while the vascular trunk is formed as post-truncal fetal lesions. Therefore, they pres- ent as a deformed vein with various degrees of developmental defect (e.g. agenesis/rudimen- tary deep vein), often as incomplete or imma- ture development (aplasia or hypoplasia) directly affecting the main axial veins. Therefore, the truncular lesions no longer pos- sess the evolutional potential with the risk of Table 1. Hamburg Classification of congenital vascular malformations. Malformations types according to Hamburg Classification* Predominantly arterial defects Predominantly venous defects Predominantly arteriovenous shunting defects Predominantly lymphatic defects Combined vascular defects *Based on the consensus on congenital vascular malformation through the international workshop in Hamburg, Germany, 1988, and subse- quently modified. Capillary malformation was not included. Table 2. Hamburg Classification of con- genital vascular malformations: forms and embryological subtypes. Extratruncular forms* Infiltrating, diffuse Limited, localized Truncular forms* Aplasia or obstruction Hypoplasia; aplasia; hyperplasia Stenosis; membrane; congenital spur Dilatation Localized (aneurysm) Diffuse (ectasia) *Congenital vascular malformation represents developmental arrest at the different stages of embryonic life: Earlier stage - Extratruncular form; Later stage - Truncular form. Both forms may exist together; may be combined with other various malformations (e.g. capillary, arterial, arteriovenous shunting, venous, hemolym- phatic and/or lymphatic); and/or may exist with hemangioma. Figure 1. A) Clinical condition of the margin- al/lateral embryonic vein along the lateral aspect of the left lower extremity. This unique vein structure is a persistent foetal remnant vessel following the failure of normal involu- tion/regression; B) Angiographic finding of this marginal vein, which remains only major venous drainage route for this patient with a lack of normal development of deep venous system. Therefore, surgical excision to control the venous hypertension is contraindicated. From: Lee, 2012.3 A B No n c om me rci al us e o nly Review [page 66] [Veins and Lymphatics 2014; 3:4050] recurrence but have varying degrees of hemo- dynamic consequences due to defective vein trunk either as obstructive77-80 or dilated81-84 lesion often affecting named vein trunk (e.g. femoral, popliteal, iliac veins). In addition to such defective vessel condition presented either as an obstruction (e.g. vein web, spur, annulus, or septum)85-88 or dilatation (e.g. popliteal or iliac vein ectasia/aneurysm)89-92 to cause flow disturbance, another form of hypoplasia causes venous reflux with the absence of valves known as avalvulia/avalvulo- sis. This unique condition is a hallmark of the MV. Together with atresia of the lumen of venous trunks and venous aneurysms, avalvulo- sis is relatively common VM lesion.93 MV itself is a different form of truncular VM lesion as the outcome of defective maturation; it is an embry- onic truncal vein remnant, which failed to undergo normal involutional process and per- sists/remains as the MV or the sciatic vein.1-4 Maturation and development of the main venous system in the primitive lower limb goes through three different stages: the first phase to form lateral peroneal/fibular vein draining into the cardinal vein; second phase to progress to form sciatic vein as a main vessel while medial draining vessel develop; and third/last phase to complete the evolutional process, in which the early lateral veins regresses.3,14 Failure of regression of the later- al peroneal vein will result in the existence of the MV at birth. The MV occurs in varying extent and severity (e.g. limited sciatic vein), and they are grouped together as lateral embryonic vein. Extension of the MV therefore, may be variable depending upon the limb development stage involved; in mild case it is limited within calf level before it is connected/drained into the proximal deep venous system but its entirety might remain with an extension to the thigh and even to the buttock draining into internal iliac vein. The MV persistence might have a close rela- tionship with a failure of normal development of the deep venous system; more than one third of patients with the MV are known to have a defective deep venous system (e.g. hypoplasia of femoral vein, aplasia of iliac vein). In such case, MV remains as the main draining vein of the limb although it may exist together with normal deep veins. Therefore, precise evaluation of the deep venous system is mandated for the assessment of the MV. But in general, MV has a numerous connec- tion with the perforators, sometimes huge in caliber and fragile in consistence to make its management risky. Mild/micro AV fistula has been described in cases of extensive aplasia of deep veins.78,94,95 Valveless condition of MV as an embryonic vein causes a severe reflux resulting in chron- ic venous hypertension/stasis accompanying various degree of CVI. Besides, a defective ves- sel wall that is deficient in smooth muscle also carries a high risk of thrombo-embolic events and infrequently leads to fatal PE, especially among KTS patients.36-39 Clinical assessment Correct assessment of MV together with the deep venous system is crucial for the treat- ment planning. Clinical examination is often easy to demonstrate the MV. However, collater- als or even the MV itself may not be easy to remain visible by increased subcutaneous fat or combined with extratruncular LM in which thickening of subcutis by lymphatic abnormal tissue may hide the vein.4,93 But in general, the MV can be easily con- firmed through the physical examination as an abnormal superficial draining vein of the lower limb which is sited on the lateral edge of the extremity frequently running beneath the coexisting CM known as a port wine stain.1-4 Unless it is located within thick subcutaneous fat along the swollen limb, the majority is quite visible as a protruding vein along the lateral aspect of the extremity invariably detected by a light palpation. Laboratory evaluation for the diagnosis of the MV is sufficient only with non- to less- invasive tests based on the Duplex ultrasonog- raphy (DUS), magnetic resonance imaging, and/or computerized tomography. DUS is the test of choice to assess the hemodynamic sta- tus of the MV and the deep vein system simul- taneously (e.g. extent and severity of the reflux and outflow resistance). The deep vein system should be assessed both in lying and standing position to differentiate among normal, aplas- tic and hypoplastic venous segments. DUS is also excellent for the mapping of the MV course to delineate entire length of MV, located supra- and sub-fascially, and site and size of perforators besides the extension of reflux.8,22 Further evaluation with invasive tests (e.g. direct puncture phlebography together with ascending phlebography) can be deferred till needed as a road map for the surgical intervention8,22,93 (Figure 2). Figure 2. A) Clinical appearance of venous malformation (VM) lesion affecting the right lower extremity as a hemolymphatic malformation, mixed with lymphatic malformation and capillary malformation, often known as Klippel-Trenaunay syndrome. B) Magnetic resonance imaging finding of extratruncular VM lesion diffusely infiltrating in the soft tissue and muscles of right lower extremity. C) Whole body blood pool scintigraphy (WBBPS) findings of massive abnormal blood pool throughout entire right lower extremity; this WBBPS effectively ruled out any additional lesions throughout the body. D) Transarterial lung perfusion scintigraphy (TLPS) study that is negative for abnormal arteriovenous shunting - 2.9% is within normal range. E) Radionuclide lymphoscintig- raphy findings of anatomically normal, but functionally abnormal double (deep and superficial) lymphatic transporting vessel, visualized along right lower extremity. This finding is consistent with a clinical finding of chronic lymphedema secondary to hypoplasia of the superficial lymphatic system, which is well compensated by deep sys- tem. From: Lee et al., 2007.21 No n c om me rci al us e o nly Review [Veins and Lymphatics 2014; 3:4050] [page 67] Arteriography seldom needed unless needed to rule out the AVM involved. Proper technique should be known to per- form the phlebography correctly in case of a large MV, because standard phlebography may show only the MV itself with poor demonstra- tion of the deep venous system even if this is normal, bringing to a wrong conclusion of aplasia of deep veins. Therefore, phlebography should be combined with DUS, and phlebogra- phy alone should be avoided.1,96 A significant numbers of the MV accompany limb-length discrepancy either as an elonga- tion or shortening of the affected limb. Hence, the assessment of the MV among KTS patients should be extended to possible involvement of angio-osteohypertrophy/hypotrophy known as vascular bone syndrome.97-100 Inconsistent terminology that characterizes the MV with the terms superficial, embryonic etc. has brought significant confusion. From the anatomical stand point the term superficial is a misnomer; although the MV remains in the superficial compartment of the lower extremity, it frequently penetrates the deep fascia and involves muscles of the deep com- partment and remains with the high risk of potentially fatal thromboembolic events associ- ated with the MV thrombosis like other major deep vein thrombosis (DVT). From a therapeutic standpoint, evaluation for the MV deserves a special consideration on the hemodynamic alterations associated with blood stasis in these frequently valveless, trun- cal VM, carrying a high risk for thrombo- embolic events: DVT and PE. Management Anticoagulation is critical to the manage- ment of the MV due to its natural thrombosis prone condition; prophylactic anticoagulation with the weight adjusted low molecular weight heparin (LMWH) is generally recommended in all patients with the MV whenever possible.101-104 Especially when the MV is further combined with an aplastic or hypoplastic iliac-femoral venous system and the MV remains the major venous outflow of the lower extremity where the normal deep venous system is absent, the anticoagulation is essential. In this subgroup, thrombus within the vein would cause serious and often fatal PE.105-108 Nevertheless, MV is generally indicated for the removal whenever feasible to prevent if not control various acute as well as chronic com- plications: CVI, VTE, and vascular bone syn- drome, as explained in previous section. But the feasibility of the surgical ablation of the MV will depend solely on the deep vein system status; only when the deep system is in normal condition, sudden increase of the venous influx following the removal of the MV can be tolerated by the deep system. If not tolerate, it would precipitate acute venous stasis and sub- sequent venous hypertension to cause acute venous gangrene. The MV among the children in particular with evidence to cause a limb-length discrep- ancy should be removed as soon as possible in order to give a sufficient time for natural com- pensation to correct leg length discrepan- cy.13,109 In cases with normal deep veins, com- plete surgical resection of the MV either in a single stage or multiple stages remains the best and most ideal treatment to control the angio-osteodystrophy.97-100,110,111 When the deep vein system is in minimally hypoplastic condition, the MV can be removed in multistages to give a sufficient time for hypoplastic vein to be dilated spontaneously to tolerate new hemodynamic status following the resection of the MV to insure rerouting of venous flow.110,111 In cases of aplasia of the deep veins, the embryonal vein becomes a part of the main draining vessel of the limb and resection is no possible. Therefore, surgical excision of the MV remains the treatment of choice in general and should be carried on to correct abnormal hemodynamic condition to cause various mor- bidities although endoluminal thermal abla- tion is occasionally technically feasible. Even for the patients with mildly hypoplastic deep veins it would be worthy for a trial as long as it would not compromise lower extremity blood return. In this subgroup of patients periopera- tive anticoagulation with LMWH should be considered. The endovascular obliteration using the laser or radiofrequency is seldom technically applicable for the MV management due to extremely superficial location of the MV right beneath the skin, which makes sufficient tumescent anesthesia difficult. Therefore, cur- rently available endovascular ablation by laser or radiofrequency is generally unsuitable for the MV under thin skin because of high risk of skin damage.4,8,22 Foam sclerotherapy is also less effective and often difficult due to extremely large venous volume and relatively fast venous flow through the MV. Further, it is risky for DVT especially when large perforators are involved with potential extension of thrombosis to the deep vein system without barrier. But the surgical excision is also often tech- nically difficult due to extreme fragility of the defective vein with lack of media, huge and fragile perforators, and/or dense dysplastic lymphatic tissue surrounding the vein to dis- sect. Due to high risk of bleeding, the tourni- quet is strongly recommended during the sur- gical procedure whenever applicable and closed stripping is often contraindicated. MV patients who are candidates for surgical removal, should receive perioperative antico- agulation with LMWH.112 Nevertheless, the results of surgical excision are good; recur- rence has not been reported.113 Conclusions Marginal vein is one of venous malforma- tions due to defective development of venous trunk formation during the later stage of embryogenesis. MV is not an ordinary varicose vein but an embryonic vein with defective ves- sel structure; it therefore, accompanies high risk of venous thromboembolism in addition to chronic venous insufficiency caused by lack of venous valves (avalvulosis). As far as the deep vein system is normal, early ablation should be done whenever feasible especially when com- plicated with leg length discrepancy. References 1. Mattassi R. Approach to marginal vein: current issue. Phlebology 2007;22:283-6. 2. Vollmar J, Voss E. Vena marginalis later- alis persistens - the forgotten vein of the angiologists. Vasa 1979;8:192-202. 3. Lee BB. 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Les malformations veineuses congénitales: évolution des concepts actuels de diagnostic et de traitement. Angéiologie 1998;50:17-9. 55. Lee BB, Baumgartner I, Berlien HP, et al. Consensus document of the International Union of Angiology (IUA) - 2013. Current concept on the management of arterio- venous management. Int Angiol 2013; 32:9-36. 56. Lee BB. Chapter 76: Mastery of vascular and endovascular surgery. In: Zelenock GB, Huber TS, Messina LM, et al., eds. Arteriovenous malformation. Phila - delphia, PA: Lippincott, Williams and Wilkins; 2006. pp 597-607. 57. Lee BB, Lardeo J, Neville R. Arterio- No n c om me rci al us e o nly Review [Veins and Lymphatics 2014; 3:4050] [page 69] venous malformation: how much do we know? Phlebology 2009;24:193-200. 58. Lee BB, Laredo J, Deaton DH, Neville RF. Chapter 53: Arteriovenous malforma- tions: evaluation and treatment. In: Gloviczki P, ed. Handbook of venous disor- ders: guidelines of the American Venous Forum. 3rd ed. London: A Hodder Arnold: 2009. pp 583-593. 59. Lee BB, Laredo J, Seo JM, Neville R. Chapter 29: Treatment of lymphatic mal- formations. In: Mattassi R, Loose DA, Vaghi M, eds. Hemangiomas and vascular malformations. Milan: Springer-Verlag; 2009. pp 231-250. 60. Lee BB, Villavicencio JL. Primary lym- phedema and lymphatic malformation: are they the two sides of the same coin? Eur J Vasc Endovasc Surg 2010;39:646-53. 61. Lee BB, Andrade M, Bergan J, et al. Diagnosis and treatment of primary lym- phedema - consensus document of the International Union of Phlebology (IUP) - 2009. Int Angiol 2010;29:454-70. 62. Lee BB, Laredo J, Neville R. Chapter 51: Primary lymphedema as a truncular lym- phatic malformation. Section XI - Lymphedema and congenital vascular malformation. In: Lee BB, Bergan J, Rockson SG, eds. Lymphedema: a concise compendium of theory and practice. 1st ed. London: Springer-Verlag; 2011. pp 419-426. 63. Noel AA, Gloviczki P, Cherry KJ Jr, Rooke TW, Stanson AW, Driscoll DJ. Surgical treatment of venous malformations in Klippel-Trenaunay syndrome. J Vasc Surg 2000;32:840-7. 64. Gloviczki P, Hollier LH, Telander RL, et al. Surgical implications of Klippel- Trenaunay syndrome. Ann Surg 1983;197:353-62. 65. Lee BB, Laredo J. Chapter 21: Classification: venous-lymphatic vascular malformation. Part 3. In: Allegra C, Antignani PL, Kalodiki E, eds. News in phlebology. Turin: Ed. Minerva Medica; 2013. pp 91-94. 66. Kim KH, Kim HH, Lee SK, et al. OK-432 intralesional therapy for lymphangioma in children. J. Korean Assoc Pediatr Surg 2001;7:142-6. 67. Park JH, Kim DI, Huh S, et al. Absolute ethanol sclerotherapy on cystic lymphan- gioma in neck and shoulder region. J Korean Vasc Surg Soc 1998;14:300-3. 68. Lee BB, Kim DI, Whang JH, Lee KW. Contemporary management of chronic lymphedema - personal experiences. Lymphology 2002;35:450-5. 69. Lee BB, Laredo J, Kim YW, Neville R. Congenital vascular malformations: gen- eral treatment principles. Phlebology 2007;22:258-63. 70. Lee BB, Laredo J. Multidisciplinary approach in the management of a giant arteriovenous malformation in the right axillary region. J Vasc Surg 2008;48:775-6. 71. Jeon YH, Do YS, Shin SW, et al. Ethanol embolization of arteriovenous malforma- tions: results and complications of 33 cases. J Kor Radiol Soc 2003;49:263-70. 72. Lee BB, Laredo J. Classification of con- genital vascular malformations: the last challenge for congenital vascular malfor- mations. Phlebology 2012;27:267-9. 73. Lee BB, Laredo J, Deaton D, Neville R. Chapter 82: Endovascular treatment of some congenital diseases - hemangioma and vascular malformation. Section XI, Textbook of peripheral vascular interven- tions. In: Heuser RR, Henry M, eds. Informa healthcare. 2nd ed. London: Informa Ltd.; 2008. pp 712-722. 74. Lee BB. Chapter 41: Congenital vascular malformation. In: Geroulakos G, van Urk H, Hobson II RW, Calligaro KD, eds. Vascular surgery. 2nd ed.: cases, ques- tions and commentaries. London: Springer-Verlag; 2006. pp 377-392. 75. Lee BB. Chapter 40: Congenital vascular malformation. In: Geroulakos G, van Urk H, Hobson II RW, Calligaro KD, eds. Vascular surgery: cases, questions and commentaries. London: Springer-Verlag; 2003. pp 315-323. 76. Lee BB, Beaujean M. Nouvelles strategies dans la prise en charge des malforma- tions vasculaires congenitales (MVC): un apercu de l’experience clinique Coreenne. Angeiologie 2004;56:11-25. 77. Eifert S, Villavicencio JL, Kao TC, et al. Prevalence of deep venous anomalies in congenital vascular malformations of venous predominance. J Vasc Surg 2000;31:462-71. 78. Belov S. Congenital agenesis of the deep veins of the lower extremity: surgical treatment. J Cardiovasc Surg 1972;13:594. 79. Raju S, Hollis K, Neglen P. Obstructive lesions of the inferior vena cava: clinical features and endovenous treatment. J Vasc Surg 2006;44:820. 80. 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Venous obstruction and jugular valve insufficiency in idiopathic intracranial hypertension. J Neurol 2009;256:964-9. 87. Wang ZG, Jones RS. Budd-Chiari syn- drome. In: Wang ZG, Jones RS, eds. Current problems in surgery. New York, NY: Mosby; 1996. pp 83-211. 88. Lee BB, Laredo J, Deaton D, Neville R. Chapter 83: Endovascular management of Budd-Chiari syndrome – suprahepatic inferior vena cava occlusive disease. Section XII, Textbook of peripheral vascu- lar interventions. In: Heuser RR, Henry M, eds. Informa healthcare. 2nd ed. London: Informa Ltd.; 2008. pp 725-731. 89. Ilijevski NS, Radak S, Novakovic B, et al. Images in vascular medicine. Jugular vein aneurysm - ultrasonographic evalua- tion. Vasc Med 2006;11:51. 90. Fishman G, DeRowe A, Singhal V. Congenital internal and external jugular venous aneurysms in a child. Br J Plast Surg 2004;57:165-7. 91. Kersting S, Rössel T, Hinterseher I, et al. Isolated aneurysm of the internal jugular vein. Vasa 2008;37:371-3. 92. 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