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What is FAVA?

Fibro-adipose vascular anomaly (FAVA) is a rare, but painful, vascular anomaly in which a significant portion of a muscle in one of a child's limbs is taken over by tough, fibrous, fatty tissue. In addition to muscle tissue changes, FAVA can also cause abnormalities in the veins or lymphatic vessels.

Symptoms & Causes

What are the symptoms of FAVA?

The most common symptoms of FAVA are:

  • Pain, often severe, in the affected limb
  • Difficulty moving the affected limb and contracture (such as a fixed bending of the arm or flexing of the ankle)
  • Mild enlargement of the limb with some visible veins

Patients have been diagnosed with FAVA anywhere between infancy and adulthood but the majority are older children, teens or young adults.

What causes FAVA?

No one knows what causes FAVA, though recent research revealed mutations in a gene called PIK3CA in some — but not all — cases. It appears to be a spontaneous condition, and is not inherited or passed along in families.

Diagnosis & Treatments

How is FAVA diagnosed?

Diagnosing fibro-adipose vascular anomaly can be challenging because some of its features overlap with other vascular anomalies, such as venous malformations. In addition to a complete medical history and thorough physical exam, the following imaging tests appear to be the most effective means of diagnosing FAVA:

How is FAVA treated?

There is no single widely accepted treatment for FAVA. However, most therapeutic approaches involve removal of the abnormal veins and lymphatic vessels present in this condition. More complex cases may require medication management or other minimally invasive procedures.

Treatment options for FAVA include:

  • Cryoablation: Sometimes called cryotherapy, this minimally invasive procedure uses extreme cold to destroy painful or diseased tissue.
  • Sirolimus: For patients who cannot be treated with cryotherapy, we use medication management with sirolimus. Also known as rapamycin, this oral medication is an immunosuppressant that has been found to improve symptoms, including pain, and slow the growth of abnormal lymphatic vessels.
  • Embolization: This minimally invasive, image-guided treatment involves injecting a special material or a device into a blood vessel in order to block or close it.
  • Surgery: Options include tendon lengthening to relieve difficulties in extending or flexing the affected limb or removing the fatty, fibrous tissue that makes up the anomaly.
  • Physical therapy: Therapists work with children to ease pain and increase range of movement in a limb affected by FAVA.

For our patients with complex vascular syndromes or other conditions in addition to FAVA, we can combine cryoablation with other treatments. These patients may undergo sclerotherapy, embolization and cryoablation in one or two sessions — reducing the number of hospital stays and shortening your child’s recovery time.

How we care for FAVA

Because FAVA was first identified as a unique condition by clinicians at Boston Children’s Hospital, we have the depth of knowledge to ensure an accurate diagnosis. Once a diagnosis and the extent of the disease are confirmed, the team at the Vascular Anomalies Center will work with you to develop a coordinated care plan that matches your child's specific needs. The team brings the expertise of other Boston Children's departments and services as necessary to provide your child with the best care in a family-friendly atmosphere.

Research & Innovation

Our areas of innovation for FAVA

Researchers and clinicians in the VAC conduct research that may lead to the development of new, more effective therapies and ways to prevent FAVA and other anomalies. Members of our team published the first paper that defined FAVA as a unique vascular anomaly, and recently identified mutations in a gene called PIK3CA in tissues from several patients with FAVA. Also, in a recent retrospective review study, VAC clinicians determined that image-guided percutaneous cryoablation (a procedure where a clinician partially freezes a FAVA lesion) is an effective and safe option for controlling pain associated with FAVA.