A lipoma looks like a small, rounded lump just beneath the skin that feels soft and doughy, almost like a rubber ball embedded in tissue. Most are less than 2 inches (5 centimeters) across, and the skin covering them appears completely normal, with no discoloration, redness, or texture changes. If you press on one, it slides easily under your fingertip, which is one of its most distinctive traits.
How a Lipoma Looks and Feels
Lipomas are slow-growing masses of fat cells enclosed in a thin capsule. They sit in the layer of fatty tissue between your skin and the underlying muscle, giving them a characteristic depth. You can usually see a gentle dome-shaped bulge, but because the overlying skin stays unchanged, smaller lipomas are often easier to feel than to see.
When you touch one, it has a soft, spongy quality. It moves freely when you push it with a finger, sliding a short distance to the side before settling back. This mobility is a hallmark. A lipoma is painless in most cases, though it can cause discomfort if it presses against a nearby nerve or sits in a spot that gets squeezed by clothing or body movement.
One subtype, called an angiolipoma, contains blood vessels in addition to fat. These look similar on the surface but tend to feel more tender or outright painful when touched, with a slightly firmer, spongier texture than a typical lipoma.
Common Locations on the Body
Lipomas show up most often on the neck, shoulders, back, abdomen, arms, and thighs. They tend to appear in areas with a thick layer of subcutaneous fat. Some people develop just one; others develop several over the years. Having multiple lipomas is relatively common and usually follows the same pattern of slow, painless growth at each site.
Because lipomas grow between layers of tissue rather than within the skin itself, they don’t form a visible opening or pore on the surface. This is one way they differ from cysts, which sometimes show a small central dot or punctum.
Size and Growth Rate
Most lipomas measure between 1 and 2 inches across, roughly the size of a grape to a golf ball. They grow slowly, often over months or years, and many people notice them only after they’ve been present for a while. In rare cases, a lipoma can exceed 6 inches in diameter, but this is uncommon.
The slow growth rate matters because it helps distinguish lipomas from more concerning lumps. A mass that doubles in size within a few months behaves differently from a typical lipoma and warrants closer evaluation.
How Lipomas Differ From Cysts
People often confuse lipomas with cysts because both create a visible or palpable lump under the skin. The differences are easy to spot once you know what to check:
- Texture: A lipoma feels soft and doughy. A cyst feels firmer, more like a pea or marble under the skin.
- Mobility: A lipoma slides freely under your finger. A cyst tends to stay more anchored in place.
- Pain: Lipomas are typically painless. Cysts are often tender to the touch and can become red, swollen, or painful if they rupture or get infected.
- Skin changes: The skin over a lipoma looks normal. Cysts may cause redness, swelling, or a visible central opening.
How Doctors Confirm a Lipoma
In most cases, a doctor can identify a lipoma through a physical exam alone. The combination of softness, mobility, and a slow growth history is distinctive enough. If the lump is larger than about 5 centimeters, sits deeper than usual (below the layer of muscle fascia), or has any unusual features, imaging becomes part of the evaluation. An ultrasound is the most common first step. On ultrasound, lipomas typically appear as well-defined, oval masses with a thin capsule and fine internal lines running parallel to the skin.
If there’s any concern that a lump could be something other than a benign lipoma, a doctor may order an MRI or CT scan, or take a small tissue sample (biopsy) to examine under a microscope.
Warning Signs That a Lump Isn’t a Lipoma
A cancerous fatty tumor, called a liposarcoma, is rare but worth knowing about because it can initially resemble a lipoma. The key differences are behavioral rather than purely visual. A liposarcoma tends to grow rapidly, feels hard or firm rather than soft, doesn’t move easily when pressed, and is often painful.
Specific red flags to pay attention to:
- Rapid growth: A lump that doubles in size over roughly three months is growing faster than a lipoma should.
- Firmness: A hard, immovable mass behaves differently from the soft, sliding feel of a lipoma.
- Persistent pain: Pain that isn’t simply from the lump pressing on something, but is constant or worsening.
- Large size: Lumps larger than 5 centimeters on the body receive closer scrutiny, especially if they sit deep below the skin surface.
None of these signs alone confirms cancer, but any of them changes the urgency of getting the lump evaluated. A standard lipoma that has been stable for months or years, feels soft, moves freely, and causes no pain is overwhelmingly likely to be benign.