Hemangiomas and Other Vascular Anomalies

Abstract

A wide spectrum of vascular anomalies exists and the International Society for the Study of Vascular Anomalies (ISSVA) have classified all known lesions as either vascular tumors (benign, borderline, malignant) or vascular malformations (capillary, venous, arteriovenous, combined, syndromic of vessel specific).

Infantile hemangiomas (IH) are both the most common vascular tumor and vascular anomaly. They usually only appear in the first few weeks of life and undergo a characteristic proliferation phase from about 3 months of life with a plateau phase around a year of age followed by an involution phase, which takes many years. Propranolol has proven a very successful medical therapy at managing IH complicated by ulceration or functional impairment, e.g., paraglottic, periocular. Congenital hemangiomas are fully grown at birth and exhibit either rapid involuting or non-involuting behavior, the latter of which require surgical resection if complicated by pain, ulceration, or cosmetic/functional impairment, although some can be managed with pulsed-dye laser therapy. Kaposiform hemangioendotheliomas are borderline tumors which invade locally but do not metastasize. They can be associated with a potentially fatal constellation of severe thrombocytopenia and coagulopathy known as Kasabach-Merritt phenomenon and vincristine is now the first-line medical therapy for unresectable lesions, which constitutes most lesions. Any child with ≥5 cutaneous hemangiomas should be screened for hepatic hemangiomas, which, if large (multifocal or diffuse) can give rise to high-output cardiac failure or consumptive hypothyroidism.

Capillary malformations (port-wine stains) are the most common form of vascular anomaly. Large (segmental) capillary malformations may be associated with underlying spinal or CNS abnormalities and they may form part of a wider disorder, such as capillary malformation-arteriovenous malformation syndrome. Venous malformations are largely sporadic but challenging to treat. They may be complicated by thrombosis, pain, and expansion, especially peripubertally. Compressive garment therapy is the basic mainstay of treatment, with sclerotherapy being the first-line treatment for complicated lesions. Arteriovenous malformations may occur in isolation or as part of a wider overgrowth disorder, such as Parkes Weber syndrome. They follow a well described life cycle, and when they complicate with ulceration, pain, and expansion, treatment with embolization with or without surgical resection is often necessary. With many vascular malformations and some vascular tumors, treatment is often with the intent of symptom control and functional preservation rather than curative intent.

Vascular anomalies are best managed in a center with a specialized multidisciplinary team with dermatology, surgery, interventional radiology, and appropriate adjunct specialists. A range of antiangiogenic pharmacotherapies are becoming available which may have a role in the management of patients with vascular malformation-associated overgrowth disorders such as Klippel-Trenaunay syndrome and CLOVES syndrome.