Epidemiology
Vascular malformations are developmental abnormalities of the blood vessels, present from birth; they usually grow along with the person and persist into adulthood. Unlike vascular tumors (such as a hemangioma), they are not overgrowths of cells. Swelling with exertion, heat, or when the limb is held down can point to a venous or lymphatic component and change management.
Basic features
They are described by the type of vessel and the flow: low-flow (venous, lymphatic, or capillary) and high-flow (arteriovenous). They can cause swelling, pain, changes in skin color, or symptoms that vary with activity, depending on their depth and type.
Usual treatment
Management is defined by a team experienced in vascular anomalies and depends on the type, flow, location, and symptoms: it ranges from observation and conservative measures (compression, physiotherapy, pain relief) to sclerotherapy for low-flow venous or lymphatic malformations, embolization for high-flow arteriovenous ones, and surgery in selected cases. In complex malformations, or those with overgrowth of the limb, alterations of the PIK3CA/mTOR pathway are now investigated, because targeted treatments exist (sirolimus and, in selected cases, alpelisib) that can reduce the volume and the symptoms. There is no single treatment sequence that applies to every case.
Outcomes and prognosis
They are not solid tumors that are 'cured' in one step: they may persist or come back and often require step-by-step, long-term management tailored to the type of malformation.