Venous Malformation

What is a venous malformation?

A venous malformation (VM) is a bluish lesion caused by widened, abnormally shaped veins. While rare, VMs are the most common kind of vascular malformation treated at the Boston Children's Hospital's Vascular Anomalies Center.

The blood vessel walls in a venous malformation are unusually thin and have relatively little smooth muscle around them, allowing them to stretch abnormally. A VM can be large or small and can enlarge as a child grows older.

Children can have multiple VMs and may experience a wide range of symptoms based on where the malformation occurs and its size. A child may have just an isolated VM or have them as part of an underlying condition. VMs do not go away on their own and often recur after treatment.

Are there different types of venous malformations?

There are also rare sub-types of venous malformations, which make up approximately 10 percent of all VMs such as:

  • Glomuvenous malformation (GVM): Glomus cells are smooth muscle cells that are believed to regulate blood flow. Glomus cells in GVMs are shaped abnormally.
  • Cerebral-cavernous malformation (CCM): CCM is a familial disorder characterized by the formation of multiple VMs in the brain. These lesions often bleed and expand. About 10 percent of kids with this disorder develop skin VMs.
  • Blue rubber bleb nevus syndrome (BRBNS): Children with BRBNS typically have multiple VMs of the skin and internal organs.
  • Maffucci syndrome: Children with this condition have multiple benign bone tumors (enchondromas) and VM-like lesions of the skin.

What are the symptoms of venous malformations?

Venous malformations (VMs) most commonly appear on the skin but can be present in other tissues and organs as well. They are typically blue, soft, and compressible.

They can range in size from a very small lesion in one spot to widespread lesions that also affect the underlying tissue, muscles, and bones. They can also arise on their own or as part of an underlying condition like blue rubber bleb nevus syndrome.

VMs can appear anytime during childhood, adolescence, or adulthood. Most are present at birth, though they may not be apparent or diagnosed until later — especially if the malformation is small or not in an obvious location.

The symptoms of a VM depend on the malformation's size and location and most commonly include:

  • pain
  • swelling
  • psychological/social issues related to the appearance of the lesion

What causes venous malformations?

VMs are caused by genetic mutations that arise during the embryonic stage of life. No known food, medication, or activity during pregnancy can cause a VM.

What are the most common venous malformation complications?

Some possible complications include:

  • pain when the VM suddenly expands if a clot forms
  • growth as the result of injury or during puberty
  • obstruction of vital functions like breathing or vision
  • fractures of the affected bone, and arthritis with limbs impacted by VMs
  • a pulmonary embolism if a large VM affects a child’s deep venous system
  • chronic bleeding and anemia with gastrointestinal VMs

How we care for venous malformations

The Vascular Anomalies Center at Boston Children's takes an interdisciplinary approach to care of children with venous malformations, whether the child is initially reviewed at our conference or seen in clinic. On your first visit to clinic, several VAC specialists will often review your child's case at the same time. Our experience in treating over 2,000 patients with venous malformations gives us the depth of knowledge to ensure you have an accurate diagnosis.