Chapter 60: Vascular Anomalies

BACKGROUND

More than one-third of infants are born with a vascular birthmark.¹ Although most of these lesions are benign and uncomplicated, a minority require treatment and inpatient care. The pediatric hospitalist should be able to recognize major types of vascular anomalies and identify lesions requiring referral to, or immediate medical care in collaboration with, vascular anomaly specialists in fields such as dermatology, surgery, hematology/oncology, pathology, orthopedics, and radiology.

In 1996, vascular anomalies were reclassified into two main categories: malformations and tumors (Table 60-1).^2,3 Vascular malformations are comprised of structurally abnormal vessels with normal endothelial turnover, and are subcategorized based on their endothelial components (e.g. capillary, venous, lymphatic, and/or arteriovenous) and flow characteristics (i.e. slow flow vs. fast flow). These anomalies may be stable or progressive; they generally do not regress. In contrast, vascular tumors arise by endothelial hyperplasia, and may be benign, borderline, or sometimes malignant.

VASCULAR MALFORMATIONS

Capillary malformations (also known as “port-wine stains”) are slow-flow lesions that may be focal, regional, or diffuse. Clinically, capillary malformations are pale pink to deep red blanching patches that are present at birth and generally permanent. Over time, some lesions, particularly those on the face, may darken, thicken, and become more nodular. Regional and diffuse capillary malformations may be associated with soft tissue or bony overgrowth or undergrowth.

Fading macular stains of infancy (also referred to as “angel’s kisses,” “stork bites,” or “salmon patches”) are a subset of capillary malformations located on the glabella, eyelids, forehead, and posterior neck. Unlike the typical vascular malformation, these lesions may fade or disappear entirely after 1 to 2 years of life; however, some lesions, particularly those on the nape of the neck, may persist.

Venous malformations (sometimes called “venous angioma” or “cavernous hemangioma”) are slow-flow vascular malformations comprised of irregular, dilated venous channels. Lesions are present at birth, though they may not be clinically evident. Typically, venous malformations present as soft, compressible bluish papules, nodules, or masses that tend to become more prominent with age, dependency, and physical activity (Figure 60-1). Lesions may be confined to the skin and subcutaneous tissue, or may involve deeper structures such as muscle, bone, and viscera. Diminished or stagnant blood flow within ectatic venous channels may lead to production of thrombin and conversion of fibrinogen to fibrin, resulting in chronic localized intravascular coagulation with episodes of localized thrombosis or bleeding.⁴