2017 Sec 1 Green Book

Table 2. International Society for the Study of Vascular Anomalies Classification of Vascular Anomalies (Simplified and Adapted from www.issva.org)

VASCULAR ANOMALIES

Vascular tumors

Locally aggressive or borderline vascular tumors

Benign vascular tumors

Malignant vascular tumors

Infantile hemangiomas Congenital hemangiomas -Rapidly involuting -Noninvoluting -Partially involuting Tufted angioma Epithelioid hemangioma Others

Kaposiform hemangioendothelioma Retiform hemangioendothelioma Kaposi sarcoma Others

Angiosarcoma Epithelioid hemangioendothelioma Others

Vascular Malformations

Simple vascular malformations

Capillary malformations

Lymphatic malformations

Arteriovenous malformations

Venous malformations

Arteriovenous fistula

-Cutaneous and/or mucosal -Telangiectasia -Cutis marmorata telangiectatica congenital -Nevus simplex -Others

-Common -Generalized lymphatic anomaly -Gorham-Stout disease -Channel type -Primary lymphedema -Others

-Common -Familial

-Sporadic -In hereditary hemorrhagic telangiectasia -In capillary malformation – arterio-venous malformation syndrome

-Sporadic -In hereditary hemorrhagic telangiectasia -In capillary malformation – arterio-venous malformation syndrome

cutaneo-mucosal -Blue rubber bleb nevus syndrome -Glomuvenous -Cerebral cavernous malformation -Others

Combined vascular malformations

Anomalies of major named vessels

Vascular malformations associated with other anomalies

macrocystic, microcystic, or mixed. The typical location is pos- terior to the SCMmuscle. However, microcystic lesions tend to occur above the mylohyoid level in the oral and perioral struc- tures and submandibular spaces and may involve the parotid gland. Lymphatic malformations have a tendency to infiltrate across various cervical spaces or extend into the mediastinum and adjacent anatomic structures are encircled/wrapped rather than displaced. Typical imaging characteristics include the trans-spatial extension including engulfment and encasement of neurovascular structures as well as fluid-fluid levels in a multilocular cystic structure with macrocystic and/or micro- cystic elements. On US, echogenic appearance of parts of the lesion is due to clusters of small abnormal lymphatic channels. The content of the cystic elements varies from homogenous to heterogeneous due to prior hemorrhage or infection. 1,3,35 The hemorrhagic component or debris from previous infection layering in the dependent portion of the cystic elements causes the fluid-fluid levels. Postcontrast MR imaging sequences and multiphasic time-resolved dynamic cMRA typically show no contrast enhancement but may demonstrate enhancement of the walls and septa of the cystic elements, particularly in case of concomitant (prior) infection (Fig 12). 7 The presence of a lymphatic malformation in the posterior cervical triangle may be associated with Turner syndrome and trisomy 21, 18, and 13. 3,12

Venous Malformation Venous malformations are the most common low-flow vascular malformations and the second most common vascular lesions of the head and neck region (after hemangiomas). In the neck re- gion, the lesions manifest at birth or in early infancy (although they may stay dormant till adulthood) as a painless soft blue or purplish mass or may be symptomatic depending on po- tential accompanying local inflammatory changes. Local pain, bleeding, and cosmetic concerns are the leading symptoms at the time of presentation. Venous malformations are develop- mental anomalies composed of dysmorphic venous channels lined by flattened endothelium. They are characteristically lo- cated in the skeletal muscles of the neck, including the mas- seter, pterygoid, trapezius, and SCM muscles, or may involve the mandibular region. The presence of phleboliths is a key imaging feature of venous malformations. US demonstrates a compressible, hypoechoic heterogeneous lesion with detectible flow on Doppler in about 40% of the cases. 35 The phleboliths appear as hyperechoic foci and show posterior acoustic shad- owing. On MR imaging studies, trans-spatial extension of the venous malformation may be identified. The lesion is typically T1- isointense and T2-hyperintense to normal muscle, with het- erogeneous contrast enhancement. Distinct areas of T2 hyper- intense signal may represent venous lakes. Fluid-fluid levels

Dremmen et al: Imaging Lumps and Bumps of the Neck in Children

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