40 Vascular Anomalies
Vascular anomalies are common lesions that affect the pediatric population. The most common tumors include infantile hemangioma, congenital hemangioma, kaposiform hemangioendothelioma, and pyogenic granuloma. The most frequent malformations are capillary malformation, venous malformation, lymphatic malformation, and arteriovenous malformation. Management is based on the type of lesion and may include laser, sclerotherapy, embolization, resection, or pharmacotherapy (topical, intralesional, systemic).
Vascular anomalies are disorders that affect capillaries, arteries, veins, or lymphatics. Because these lesions usually involve the skin, the initial consultation often is with a plastic surgeon. Vascular anomalies are common, affecting 5.5% of the population. Lesions are classified biologically, based on their clinical behavior and cellular characteristics (Table 40‑1 ). The field is confusing because lesions look similar, and imprecise terminology is used (Table 40‑2).
There are two broad types of vascular anomalies: tumors and malformations. Tumors demonstrate endothelial proliferation and affect approximately 5% of the population. There are four major lesions: (1) infantile hemangioma (IH), (2) congenital hemangioma (CH), (3) kaposiform hemangioendothelioma (KHE), and (4) pyogenic granuloma (PG; Fig. 40‑1). Vascular malformations are errors in vascular development and have minimal endothelial turnover; they affect approximately 0.5% of the population. There are four major types based on the anomalous vessel(s): (1) capillary malformation (CM), (2) lymphatic malformation (LM), (3) venous malformation (VM), (4) arteriovenous malformation (AVM; Fig. 40‑2). Recently, the causative mutation for many vascular anomalies has been identified (Fig. 40‑3).
More than 90% of vascular anomalies can be diagnosed by history and physical examination (Table 40‑3). Approximately 9% of lesions require imaging for diagnosis, and less than 1% of vascular anomalies need histopathology to identify the lesion. Generally, the first-line imaging modality to confirm the type of vascular anomaly is ultrasound because it does not require sedation and is easy to perform. Magnetic resonance imaging (MRI) is used for lymphatic, venous, and AVMs to confirm their diagnosis and determine the extent of disease. Biopsy is reserved for a vascular anomaly that cannot be diagnosed despite imaging.
Sporadic venous malformation
Verrucous venous malformation
Cutaneomucosal venous malformation
Cerebral cavernous malformation
Sporadic lymphatic malformation
Familial congenital primary lymphedema
Capillary malformation–arteriovenous malformation
Hereditary hemorrhagic telangiectasia type 1 (HHT1)
Hereditary hemorrhagic telangiectasia type 2 (HHT2)
PTEN-associated vascular anomaly
Abbreviation: PTEN, phosphatase and tensin homolog.
40.2.1 Infantile Hemangioma
IH is the most common tumor of infancy, affecting 4 to 5% of infants. IH is more frequent in premature children and in females (4:1). The median age of appearance is 2 weeks; 50% are noted at birth as a telangiectatic stain, pale spot, or ecchymotic area. IH grows faster than the child during the first 9 months of age (proliferating phase); 80% of its size is achieved by 3.2 (±1.7) months. IH is red when it involves the superficial dermis. A lesion beneath the skin may not be appreciated until 3 to 4 months of age when it has grown large enough to cause a visible mass; the overlying skin may appear bluish. After 12 months, the tumor begins to regress (involuting phase); the color fades and the lesion flattens. Involution ceases in most of children by age 4 years (involuted phase). After involution, one-half of children will have residual telangiectasias, scarring, fibrofatty residuum, redundant skin, or destroyed anatomical structures.
Infants with five or more small (<5 mm) IHs have a 16% risk of having hepatic hemangiomas, which are typically asymptomatic. PHACE association consists of a plaquelike IH in a regional distribution of the face with at least one of the following anomalies: Posterior fossa brain malformation, Hemangioma, Arterial cerebrovascular anomalies, Coarctation of the aorta and cardiac defects, Eye/Endocrine abnormalities. Because 8% of children have a stroke in infancy, these patients should have an MRI to evaluate the brain and cerebrovasculature. Infants are referred for ophthalmologic, endocrine, and cardiac evaluation to rule out associated anomalies. LUMBAR association (Lower body infantile hemangioma, Urogenital anomalies, Myelopathy, Bony deformities, Anorectal malformations, Renal anomalies) typically affects the sacral area or lumbar region. Ultrasonography is obtained to rule out associated anomalies in infants less than 4 months of age. MRI is indicated in older infants or when ultrasound is equivocal.
40.2.2 Congenital Hemangioma
CHs are fully grown at birth and do not have postnatal growth. They are red-purple with coarse telangiectasias, central pallor, and a peripheral pale halo. These lesions are more common in the extremities, have an equal sex distribution, and are solitary with an average diameter of 5 cm. There are two forms: rapidly involuting congenital hemangioma (RICH) and noninvoluting congenital hemangioma (NICH). RICH involutes rapidly after birth and 50% complete regression by 7 months of age; the remaining tumors are fully involuted by 14 months. NICH, in contrast, does not regress and remains unchanged.
40.2.3 Kaposiform Hemangioendothelioma
KHE is a rare neoplasm (1/100,000 children) that does not metastasize. KHE is present at birth in 50% of patients, has an equal sex distribution, and affects the head/neck (40%), trunk (30%), or an extremity (30%). The tumor is often greater than 5 cm and is reddish-purple. Seventy percent of patients have Kasabach–Merritt phenomenon (KMP; thrombocytopenia < 25,000/mm3, petechiae, bleeding). KHE partially regresses after 2 years of age, although it usually causes chronic pain and stiffness. MRI is indicated for diagnostic confirmation and to assess the extent of the tumor.
40.2.4 Pyogenic Granuloma
PG is a solitary, red papule that grows rapidly on a stalk. It is small, with an average diameter of 6 mm; the mean age of onset is 6 years. PG commonly is complicated by bleeding (64%) and ulceration (36%). PG involves the skin (88%) or mucous membranes (11%). It is distributed on the head or neck (62%), trunk (19%), upper extremity (13%), or lower extremity (5%). In the head and neck region, affected sites include cheek (29%), oral cavity (14%), scalp (11%), forehead (10%), eyelid (9%), or lips (9%).
40.2.5 Capillary Malformation
CM (previously called “port-wine stain”) is the most common type of vascular malformation. The lesion is noticed at birth and can involve any area of the integument. Over time, the lesion progresses: (1) it darkens, (2) fibrovascular cobblestoning can occur, (3) PGs may develop, and (4) soft-tissue and bony may enlarge underneath the stain. The birthmark referred to as an “angel kiss” or “stork bite” is a fading capillary stain. It is present in one-half of Caucasian newborns and is located on the forehead, eyelids, nose, upper lip, or posterior neck. No treatment is necessary because it lightens over the first 2 years of life.
40.2.6 Venous Malformation
Although VMs are present at birth, they may not become evident until childhood or adolescence when they have grown large enough to cause a visible deformity or symptoms. Lesions are blue, soft, and compressible. Hard, calcified phleboliths may be palpable. The primary morbidity is psychosocial because most lesions affect the skin and cause a deformity. The second most common complication is pain secondary to thrombosis and phlebolith formation. Patients are not at risk for thromboembolism, unless a large phlebectatic vein is connected to the deep venous system. VMs are diagnosed by history and physical examination. Dependent positioning will cause a lesion to enlarge. Small, superficial VMs do not require further diagnostic workup. Large or deep lesions are evaluated by MRI. Approximately 10% of patients with VM have multifocal, familial lesions that are autosomal dominant: glomuvenous malformation (GVM), cutaneomucosal-venous malformation (CMVM), or cerebral cavernous malformation (CCM).
Several phenotypical subtypes of VM exist. Blue rubber bleb nevus syndrome (BRBNS) is characterized by multiple, small VMs involving the skin, soft tissue, and gastrointestinal tract. Morbidity is associated with gastrointestinal bleeding. Diffuse phlebectasia of Bockenheimer specifies an extensive extremity VM involving skin, subcutaneous tissue, muscle, and bone. Sinus pericranii refers to a venous anomaly of the scalp or face and transcalvarial communication with the dural sinus. Verrucous VM is clinically similar to a hyperkeratotic VM. Fibroadipose vascular anomaly is differentiated from intramuscular VM by significant pain, contractures, and a solid component.