A Lump Under the Skin: Cyst, Lipoma or Lymph Node?

Most people find one by accident. You are in the shower, rubbing in lotion or scratching your neck, and your fingers land on a small bump that wasn't there before, or that was always there and you never noticed. From then on, it is hard to leave alone. This is one of the most common reasons people stop by our Beechnut office, and the reassuring part is that most of these lumps turn out to be harmless. Even so, they deserve a look, because they don't all behave the same way.

In this guide, the medical team at the clinic walks you through the three lumps we see most often, what a soft tissue ultrasound adds to the picture, and which signs mean you shouldn't sit on it for weeks.

Three stories we hear all the time

Ramiro, 52. He has had a lump on his shoulder for about three years, roughly the size of a walnut. It feels soft and rubbery, slides under his fingers and has never hurt. What bothers him now is that the strap of his work backpack rubs right on top of it.

Lucía, 34. There is a small bump on her back with a dark dot in the middle. Every few months it turns red, gets sore and leaks a thick, white, smelly material. Then it settles down and the cycle starts over.

Mateo, 7. A week after a sore throat, his mom felt two little bumps under his jaw. They are a bit tender and move when she presses on them.

Each case is different, and in general terms they resemble what is usually a lipoma, a cyst and a swollen lymph node. But feeling a lump from the outside is not the same as seeing inside it, and that is where ultrasound comes in.

Lipoma: a slow-growing pocket of fat

A lipoma is a collection of fat wrapped in a thin layer of tissue. Most feel soft or doughy, shift when pushed and cause no pain. They often show up on the shoulders, back, arms, thighs or neck and can stay the same size for years. Bumping or touching one won't turn it into something else.

Plenty of people live with a lipoma for decades without trouble. Removal makes sense when the lump is bothersome, growing, or rubbing against clothing or work gear, which is exactly Ramiro's situation.

Cyst: a small sac with something inside

A sebaceous cyst (also called an epidermoid cyst) is a little sac under the skin filled with thick material. Typical clues: it sits closer to the skin surface than a lipoma, may have a pore or dark dot on top and, when inflamed, becomes red, warm and painful. Once it fills with pus, it acts like an abscess.

Squeezing a cyst at home is tempting and almost never helps. It pushes the contents deeper, makes the swelling worse and leaves a bigger scar.

Lymph node: a sign your body is busy

Lymph nodes are small filters in the immune system. You have many in the neck, behind the ears, in the armpits and in the groin. When the body is fighting a nearby infection, such as a sore throat, an infected tooth or a cut on the foot, the nodes in that area swell, feel a little sore and usually shrink back on their own over a few weeks as the infection clears. That is the most likely explanation for Mateo.

A node that keeps growing, never goes down, or appears with no infection to explain it is a different story and should be checked.

What ultrasound adds

The clinic's ultrasound and sonography page spells it out: the scans done here include thyroid and soft tissue studies for neck lumps, lymph nodes or masses under the skin. If you come in with a lump, that has some practical upsides:

• No special prep. Unlike some other scans, you don't need to fast or arrive with a full bladder.
• No radiation and no pain. A little gel goes on the skin and a handheld probe glides over the area; at most you'll feel some pressure.
• It is short. Most scans take between 15 and 30 minutes.
• It is done right at the clinic, so this part of the workup doesn't send you somewhere else.

Generally speaking, the image helps show whether a lump is filled with fluid or is solid, how big it is, what shape it has, how deep it sits and how it relates to the tissue around it. That information goes a long way: a fluid-filled lump behaves differently from a fatty one, and a lymph node looks different from a cyst.

What ultrasound can't do is settle every case on its own. Sometimes the image is enough to decide the next step; other times another test, such as a CT scan, or a tissue sample is needed. When that happens, the medical team helps arrange the referral and hands you the report to take along.

After the scan: the usual options

Once the lump has been looked at, the path tends to be one of three:

• Watch it. Many small lipomas and nodes from a recent infection only need monitoring. Writing down the size, or snapping a photo next to a coin, makes comparison easy.
• Remove it in the office. Through minor surgery, the clinic removes sebaceous cysts, lipomas and other small skin lesions under local anesthesia, with no hospital stay. If a lesion looks like it should be studied, the tissue can be sent to a pathology lab.
• Calm the inflammation first. A badly inflamed cyst is sometimes treated first and taken out once the swelling goes down. If there is already pus, abscess drainage is done under local anesthesia, and no appointment is needed.

If the lump is in the front of the neck and moves when you swallow, it may involve the thyroid rather than a lymph node. In that case the workup includes other tests described on the thyroid page.

Signs not to put off

As general information, it is worth getting checked soon, not months from now, when a lump:

• Grows quickly, over a matter of weeks.
• Feels rock-hard and fixed in place, not moving when pushed.
• Hasn't gone down after two to four weeks with no infection to explain it.
• Comes with fever, night sweats or weight loss you weren't trying for.
• Is red and warm, with redness that is spreading.
• Shows up in several places at once (neck, armpits, groin).

These signs don't mean something serious is going on; they mean the lump should be looked at now. And if a neck lump makes it hard to swallow or breathe, or a red streak runs up from an inflamed area along with a high fever, go to the emergency room or call 911.

Jot this down before you come in

Your answers matter as much as the image:

• When did you first notice it, and has the size changed?
• Does it hurt, turn red or leak anything?
• Have you recently had an infection, a wound or a dental problem near that spot?
• Do you take blood thinners or aspirin? (This matters if removal is planned later.)

Getting it checked near Alief

Clínica Hispana Cruz 4 is at 10100 Beechnut St Ste 240, Houston, TX 77072. If you found a lump and keep poking at it without knowing what it is, bring your notes and ask about a soft tissue ultrasound; if you have questions about the scan, give us a call first and we'll tell you what to expect. The medical team will walk you through what shows up on the screen, in Spanish, and what the next step looks like for you.