Fig. 45.1
Venous malformation, neck. a Intramuscular VM composed of large, irregular, thin-walled channels. A phlebolith is indicated by arrows. b The channels vary in size and are arranged back to back with scant intervening stroma. c Abnormal venous channels with flat endothelium and thin, variably muscular walls
Fig. 45.2
Venous malformation, maxillary bone. a Portion of maxillary bone with intraosseous VM associated with osteolysis (asterisks). Arrows indicate teeth and arrowheads indicate residual trabeculae of bone. b Cluster of intramedullary, thin-walled venous channels of variable size. c Back to back, thin-walled venous channels with flat endothelium and luminal red blood cells
Key Points
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VM is particularly problematic because it can expand, especially during adolescence, and often recurs after treatment.
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The majority of patients who present with asymptomatic lesions ultimately will require intervention.
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VMs should be treated in a vascular anomalies center by a multidisciplinary team.
Biology and Epidemiology
VMs arise from an error in vascular morphogenesis, which results in dilated, thin walled channels of variable size and mural thickness [1]. VM is sporadic and solitary in 90 % of patients; 10 % have multifocal, familial lesions (GVM: 8.0 % or CMVM: 2.0 %) [4, 5].
Pathophysiology
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The mechanism for VM enlargement is unknown. Atypical structural characteristics of the vein may predispose the lesion to distention causing stagnation, thrombus, pain, deformation, and/or obstruction [2].
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Lesions progress 2.6 times more often in adolescence compared to childhood, indicating that pubertal hormones may be involved in the pathogenesis of VM [2].
Molecular/Genetic Pathology
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Sporadic VMs arise from abnormal vasculogenesis; approximately one-half of lesions have a somatic mutation in the endothelial tyrosine kinase receptor TIE2 [4, 5]. Angiopoetins, the ligands for TIE2, are involved with vascular stabilization; the mutation alters endothelial–pericyte contact affecting venous development [5, 10].
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CMVM is an autosomal dominant disorder produced by a mutation in the TIE2 receptor [10].
Incidence and Prevalence
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VMs are the most common vascular malformation treated in a vascular anomalies center, comprising 36.8 % of referrals [16].
Age Distribution
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VM is present at birth, but may not become obvious until childhood or adolescence [2].
Sex Predilection
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Men and women are affected equally.
Risk Factors
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Pregnant women do not have an increased risk of VM expansion and thus pregnancy is not contraindicated [2]. Nevertheless, women with significant lesions should be cautioned about possible worsening of symptoms during pregnancy.
Relationships to Other Disease States, Syndromes
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Blue rubber bleb nevus syndrome (BRBNS) is a rare condition with multiple VMs in the skin, soft tissue, and gastrointestinal tract [21].
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Diffuse phlebectasia of Bockenheimer is an extensive extremity VM that affects the skin, subcutaneous tissue, muscle, and bone [22].
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Kippel-Trénaunay syndrome (KTS) is an eponym used to describe capillary-lymphatic-venous malformation (CLVM) of an overgrown extremity.
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Sinus pericranii is a soft tissue/cutaneous VM of the scalp or face that has a transcranial communication with the dural venous system.
Presentation
Symptoms
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Bleeding
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Head/neck VM may present with mucosal bleeding.
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BRBNS can cause gastrointestinal bleeding and chronic anemia.
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Distortion/obstruction of anatomical structures
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Head/neck VM may compromise airway or orbital function.
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Pain
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Caused by thrombosis and phlebolith formation.
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VM of muscle may result in fibrosis and contractures.
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GVMs are typically more painful than sporadic VM.
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Thrombosis
Differential Diagnosis
Arteriovenous malformation (AVM)
Capillary malformation (CM)
Congenital hemangioma (CH)
Infantile hemangioma (IH)
Kaposiform hemangioendothelioma (KHE)
Lymphatic malformation (LM)
Diagnosis and Evaluation
Physical Examination
Venous Malformation
Approximately 90 % of VMs are diagnosed by history and physical examination [24, 25]. VMs can be small and well localized, or involve multiple tissue planes and important structures. Almost all lesions involve the mucosa, skin, and/or subcutaneous tissue; 50 % also affect deeper structures (e.g., muscle, bone, joints, viscera) [4]. The primary differential diagnosis is LM.
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Findings:
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VMs are blue, soft, and compressible; dependent positioning may enlarge the lesion.
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VMs are usually > 5 cm (56 %) and solitary (99 %), they are located on the extremities (48.3 %), head/neck (30.3 %), trunk (16.6 %), or viscera (4.8 %) [16].
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VMs are slow-flow lesions; hand-held Doppler excludes fast-flow vascular anomalies (e.g., AVM, hemangioma) [6].
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Glomuvenous Malformation
Cutaneomucosal-Venous Malformation
Patients with a family history of similar lesions should be examined for CMVM. Individuals are counseled about the autosomal dominant inheritance pattern of this condition.
Laboratory Data
Imaging Evaluation
Imaging is usually performed for large or deep VMs. Small, superficial lesions typically do not require radiographical work-up.
Ultrasonography (US)
Computed Tomography (CT)
CT may be indicated if there is bony involvement [6].
Magnetic Resonance Imaging (MRI)
Venography
Venography is not required for diagnostic confirmation, but is often performed during sclerotherapy .
Pathology
Histopathological diagnosis of VM is rarely necessary, but may be indicated if imaging is equivocal. Histopathologically, VMs show abnormal, thin-walled venous channels with irregular layers of smooth muscle (see Figs. 45.1 and 45.2) [1]. Vessels frequently have thrombi or phleboliths in their lumens (see Fig. 45.1a) [1]. GVMs are characterized by abnormal venous channels surrounded by characteristic cuboidal myoid “glomus” cells (see Fig. 45.3) [1].
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