Angiolipoma is a rare type of lipoma — a growth made of fat and blood vessels that develops under your skin. Between 5 and 17 percent of lipomas are angiolipomas, according to one 2016 report. Unlike other types of lipomas, angiolipomas are often painful or tender. They can occur anywhere on the body, but most often occur on the:
- forearms (most common)
- upper arms
The growths are usually very small in size. They’re generally between 1 and 4 centimeters (cm) in diameter, but usually less than 2 cm. Most of the time, a person has many small angiolipomas at once. However, it’s possible to have only one angiolipoma at a time.
Angiolipomas are considered benign tumors. “Benign” means that the tumor isn’t cancerous or life-threatening. The condition is sometimes called lipoma cavernosum, telangiectatic lipoma, or vascular lipoma.
Angiolipomas can be classified as either noninfiltrating or infiltrating:
- Noninfiltrating angiolipomas are the most common type. They’re called noninfiltrating because they don’t penetrate (infiltrate) deeper than just below the skin. They may be painful.
- Infiltrating angiolipomas are much less common than noninfiltrating ones. They penetrate the soft tissue. They usually appear in the muscles of the lower extremities, neck, and shoulder. Infiltrating angiolipomas are usually painless. They may be more difficult to remove because they penetrate deeper into the tissues.
Angiolipomas may also be classified by where they occur in the body, especially if the angiolipoma occurs in an area that’s considered rare. For example, the following types of angiolipomas are very uncommon:
- Gastric angiolipomas. These occur in the stomach. According to one review, only four cases of gastric angiolipoma have been reported as of mid-2017. This type of angiolipoma might result in additional symptoms, like gastrointestinal bleeding and anemia.
- Spinal angiolipomas. These occur in the thoracic epidural space of the spine. This is the space located just outside the spinal cord lining of the upper and lower back. Fewer than 200 cases have been reported as of mid-2017. A spinal angiolipoma can result in weakness or tingling sensations in the body or problems with balance.
The exact cause of angiolipomas isn’t known, but they may run in families. The condition is often seen in young adults between 20 and 30 years of age. Angiolipomas rarely occur in older adults or children. They’re more common in men.
Angiolipomas may also be caused by certain medical conditions. Several angiolipomas may be due to an inherited condition known as familial multiple angiolipomatosis. These typically occur on the arms and trunk.
The use of certain medications has also been associated with the development of multiple angiolipomas. These medications include:
- Indinavir sulfate (Crixivan), a protease inhibitor used to treat HIV
- corticosteroids (like prednisone), if used long term
Other diagnostic tests useful in confirming a diagnosis include:
- Biopsy. A doctor takes a small piece of the angiolipoma and sends it to a laboratory for testing. This may be done to rule out the possibility of cancer or to differentiate an angiolipoma from another type of lipoma. In general, an angiolipoma has a higher degree of vascularity, or blood vessel development, than a lipoma.
- MRI and CT scan. Your doctor may use an MRI or CT scan to make a diagnosis. This may be the case if your doctor suspects that the growth is actually a cancerous condition called liposarcoma.
An angiolipoma is benign and not harmful, but it won’t go away on its own. If the growth is causing you pain or you’re bothered by its appearance, you can have it removed with surgery. Surgery is the only recognized treatment for removing angiolipomas.
In general, the surgery to remove an angiolipoma isn’t difficult because the growth is located just underneath the skin. Infiltrating angiolipomas may be slightly more difficult to remove. The surgery may also be more challenging if there are multiple growths to remove at once. Complications of this surgery are very rare.
Angiolipomas are benign. They won’t spread and aren’t life-threatening. Surgery to remove an angiolipoma is typically very successful, and there’s very little risk of recurrence. However, it’s possible that new, unrelated angiolipomas can appear.
Lipomas can look very similar to a rare cancer called liposarcoma. Liposarcomas even resemble fat cells when examined under a microscope. See your doctor if you notice any changes in your skin, such as discolorations, swelling, or a lump that’s hard or painful.