Practice Essentials
Venous malformations are developmental errors composed of dysmorphic channels lined by flattened endothelium exhibiting slow turnover. They present in various ways, from a vague blue patch to a soft blue mass. The lesions are always present at birth and are usually singular and solitary isolated events, although they may occur in multiple areas. Venous malformations typically involve the skin of the face, limbs, or trunk but also are found in the internal viscera and bones. They have also been identified in skeletal muscle. [1, 2] The malformations may manifest clinically in infancy, childhood, or adulthood, but depending on their location, they may remain asymptomatic throughout life. Sclerotherapy is the primary form of nonsurgical intervention for venous malformations. [3, 4, 5]
Workup in venous malformations
Most venous malformations are diagnosed based on a good history and physical examination. Magnetic resonance imaging (MRI) is the most informative imaging modality, with venous malformations appearing hyperintense of T2-weighted images. [6]
Clotting studies and a complete blood count (CBC) may be indicated in an occasional visceral lesion that is bleeding. If a particular anomaly is a diagnostic dilemma, urinary basic fibroblast growth factor (bFGF) analysis rarely may also be indicated as part of the workup.
Management of venous malformations
Sclerotherapy is the primary form of nonsurgical intervention for venous malformations. [3, 4] Larger lesions usually are treated with 95% ethanol, while cutaneous and smaller lesions are treated with sodium tetradecyl sulfate (1%). An alternative to standard sclerotherapy using sclerosant foam has been described. [7]
Surgery is indicated in isolated, symptomatic venous malformations or following sclerotherapy to improve form or function. Surgical results are a function of the size and location of the malformation.
Complicated or large venous malformations are best treated at a referral center staffed by a multidisciplinary team of diagnostic and interventional radiologists, plastic surgeons, and interested ablative surgeons (eg, neurosurgery).
History of the Procedure
The history of vascular birthmarks and anomalies is marked by misconceptions, confusing nomenclature, and folklore extending centuries into the past. [8] Birthmarks were believed to be secondary to "maternal impressions." The unborn child could be imprinted with the mother's past experiences, fears, emotions, or objects of desire. Mothers were therefore to blame for the "nevus maternus," or mother's mark. These beliefs continue to exist in many cultures around the world.
The past few decades have seen great advances in understanding of the pathophysiology, classification, nomenclature, and treatment of all vascular lesions. [9, 10] In that vein, avoid using synonyms, as they have confused the diagnosis, classification, and management of these vascular tumors. Use the appropriate terminology instead, as advocated with passion by Dr. Mulliken. [11]
Epidemiology
Frequency
Venous malformations are the most common of all vascular anomalies. Overall incidence of venous malformations is reported in 1-4% of the population. No predilection exists for either sex.
Etiology
Of venous malformations, 100% are present at birth, although not all are clinically apparent. If they are present in multiple areas, take a family history, because autosomal dominant transmission has been described for a subtype of venous malformation termed multiple glomangiomas. In addition, at least one mutation for venous malformations has been identified in a gene that codes for an endothelial receptor on chromosome 9p. [12]
Patients with Turner syndrome may have venous malformations of the intestine and feet. Another rare dominant form is represented by the familial cutaneous-mucosal venous malformation. Cerebral cavernous venous malformations could also be familial. [13]
A better understanding of the molecular mishaps that lead to vascular malformations, such as deficient tyrosine kinase receptors, may lead to new therapeutic interventions. [14, 15, 9]
Pathophysiology
Venous malformations usually manifest by childhood or early adulthood. They grow commensurately with the developing child. Unlike hemangiomas, they do not regress. [16, 17] They are by definition "slow-flow" lesions and sometimes are not obvious at birth. They can expand in response to trauma, following incomplete surgical resection, [18] or in altered hormonal states (pregnancy, puberty, steroid use). They also may expand following thrombosis or in sepsis.
The following cellular characteristics are important to remember:
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Flat endothelium, slow turnover
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Normal mast cell count
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Dysplastic walls
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Thin basement membranes
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No expression of vascular endothelial growth factor (VEGF) or basic fibroblast growth factor (bFGF)
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Low urinary bFGF
A retrospective study by Koo et al indicated that the likelihood of localized intravascular coagulopathy occurring in venous malformations is greater in patients in whom such lesions, as seen on magnetic resonance imaging (MRI), are larger, have visualized phleboliths, are located on the trunk rather than the extremities, and have a spongiform morphology. Such characteristics suggest that coagulopathy is related to larger capacitance, slower flow, and reduced physiologic compression in these malformations. The study involved 70 patients, including 37 with localized intravascular coagulopathy. [19]
Presentation
Venous malformations present in various ways, from a vague blue patch to a soft blue mass. They are easily compressible and usually swell in the dependent position or when venous pressure increases (ie, when a child cries). They may be relatively localized or quite extensive within an anatomic region. Venous malformations typically involve the skin of the face, limbs, or trunk but also are found in the internal viscera and bones. They have also been identified in skeletal muscle. [1, 2]
Episodic thromboses commonly occur in venous malformations. These are low-flow lesions. Phleboliths, secondary to phlebothrombosis, have been observed in patients as young as 2 years. They might be recognizable with plain radiography.
Indications
The most common indication for medical or surgical treatment of a venous malformation is pain. Pain is likely secondary to thrombosis of the malformation, but depends on the size and location of the lesion. Discomfort and stiffness, particularly in the morning, are associated with many larger and deep cutaneous or intramuscular malformations. Intraoral venous malformations can bleed, distort speech or dentition, or obstruct the airway. Venous malformation involving the GI tract or internal viscera can bleed, requiring intervention. Finally, treatment of venous malformations may be indicated to improve appearance or function.
Symptoms associated with venous malformations and indications for intervention vary with the organ system involved. A 3-cm venous malformation of the thigh may be asymptomatic, while the same size intracranial lesion may thrombose and lead to swelling and a life-threatening mass effect requiring emergency intervention.
Relevant Anatomy
Venous malformations represent vascular developmental errors and can occur anywhere. Their management becomes increasingly complex as they involve structures with significant neurovascular function.
Contraindications
Treatment of venous malformations, particularly surgical resection, is often greatly complicated by their deeper involvement with critical neurovascular structures. This is particularly true in the head and neck, intracranial, and extremity malformations. Surgery is often contraindicated if risks associated with the resection outweigh the presumed improvement in appearance or function that may be derived from surgery.
