Unlike malignant tumors called liposarcoma, lipomas are benign (non-cancerous) fatty tumors. The most common soft tissue tumor, they can appear anywhere, including your chest, arms, armpits, shoulders, neck, and thighs.Â
There’s no medical consensus yet on why they form, but they tend to develop slightly more often in men, especially between ages 40 and 60. Some types of lipomas (including conventional lipomas, spindle celllipomas, and pleomorphic lipomas) can run in families and may have an underlying genetic cause. But there’s no activity that predisposes people to developing them.
Lipomas have some common characteristics. They are typically:
- Symmetrical, with a round or oval shape.
- Encapsulated and moveable; they don’t spread or attach to surrounding tissue.
- Painless, though large lymphomas can become painful if they put pressure on nearby nerves.
- Less than two inches wide, though they can grow up to six inches.
Most don’t cause any problems and can be safely left alone, but a growing lipoma can affect nerves, joints, or blood vessels.
Deep-seated lipomas under the fascia (the connective tissue and collagen that provides the structure for organs and muscle) and intramuscular lipomas can create complications, such as obstruction or hemorrhage, as the fat cells grow and press on organs. Luckily, this happens very rarely—with less than 1% of all lipomas.
Before you book a removal appointment, visit a dermatologist or plastic surgeon for a lipoma diagnosis.
“Most lipomas can be identified through a physical exam alone,” says Dr. Castillo. “Additional radiological testing, like an ultrasound, CT scan, X-ray, or MRI [magnetic resonance imaging], might be performed to confirm the lipoma diagnosis, especially if the lipoma is deep within a patient's tissues.” Larger lipomas may require a biopsy.
Chicago plastic surgeon Dr. Anil R. Shah also advises that your doctor will need to rule out the possibility of a lipoma in a lymph node or a liposarcoma.
Doctors are divided on whether lipomas can turn into liposarcoma, but their appearance is the same, and neither are painful, so it’s smart to get properly diagnosed.Â
Some deep lipomas can be confused with liposarcoma. The Cleveland Clinic says, “Recognizing the difference between a lipoma and a liposarcoma (cancer) should be completed by an expert in sarcoma.”
