Symptoms depend on the type of malformation and where it is located. Symptoms usually start to occur when the malformation grows. Growth may be triggered by stressful events in the body such as puberty, pregnancy, infection, trauma and surgery.

Symptoms include, but are not limited to:

• Pain
• Swelling
• Bleeding
• Clotting
• Ulceration and wound formation
• Neuropathy – nerve involvement
• Disfigurement
• Decreased Range of Motion with resultant contractures and muscle wasting
• Compression of an organ or organ system
• Congestive cardiac failure (arterio-venous malformations)
• Overgrowth of tissue (arterio-venous malformations)

Once symptoms occur, they will usually not regress without intervention.