Lipoma removal surgery: fatty lumps under the skin and sebaceous cysts

A lipoma is a benign growth made up of fat cells. It is wrapped in a thin capsule and sits separately from the surrounding tissue, which is why it slides under the skin when you press on it with a finger. Lipomas most often appear on the shoulders, upper back, neck, arms, thighs and abdomen. Usually there is just one, but sometimes several lipomas are found on the body.

A lipoma can appear at any age, but it is most common in middle-aged people. Most lipomas are small, barely change for years and cause no pain. It is extremely rare for a lipoma itself to turn into cancer. However, in rare cases a malignant tumor of fatty tissue that looks similar (liposarcoma) is found, so a large, firm or fast-growing lump should always be shown to a doctor.

A sebaceous cyst (atheroma) forms when the duct of a sebaceous gland in the skin gets blocked. The gland can no longer release its secretion, so a sac forms inside and gradually fills with a thick, whitish, unpleasant-smelling material. Sebaceous cysts most often appear on the scalp, face and neck, behind the ears, on the back and in the groin area.

There is often a small dark dot in the center of the cyst: this is the opening of the blocked duct. If the cyst becomes infected, it turns red, swells, hurts and fills with pus. If its capsule is not removed completely, a sebaceous cyst often comes back in the same place.

These differences give you a first idea, but they are not enough for a diagnosis. A surgeon determines what the lump is by examining it and, when needed, with an ultrasound scan.

• a soft, movable, round lump under the skin;
• usually painless; it can cause discomfort when it grows, presses on a nerve or muscle, or sits where clothing or a belt rubs;
• it grows slowly over months and years;
• a sebaceous cyst has a dark dot in the center and, when inflamed, becomes red and painful and may leak pus.

Not every lump under the skin is a lipoma. A similar-looking lump can be an enlarged lymph node, a hernia (a soft bulge that gets bigger when you cough, for example at the navel or in the groin), a ganglion cyst, a fibroma, an abscess or, rarely, a malignant tumor. A painful lump next to the anus is often not a sebaceous cyst at all, but an anal abscess (paraproctitis) or a hemorrhoid (pile).

The exact cause of lipomas is unknown. Genetics may play a role: in some families, several members have multiple lipomas. Lipomas most often appear in middle age and are sometimes noticed after an earlier injury to the same area. Losing weight does not make them go away.

Sebaceous cysts are more likely with oily skin, acne, damaged hair follicles and constant friction on the skin.

A small lipoma that has not changed for years and does not bother you can simply be monitored. Removal is usually recommended when:

• the growth is getting bigger;
• it hurts, presses, or makes it hard to move or get dressed;
• it is in a visible place and bothers you cosmetically;
• the diagnosis is uncertain and you need to know for sure that the growth is benign;
• a sebaceous cyst keeps getting inflamed.

A sebaceous cyst does not go away on its own and can become inflamed at any time. That is why it is better to remove it during a calm period, when there is no inflammation.

See a surgeon without waiting if you notice any of the following:

• the lump grows noticeably over a few weeks or months;
• it is hard and uneven, stuck to the surrounding tissue and does not move;
• it hurts, or the pain is getting worse;
• it is larger than 5 cm or lies deep, under a muscle;
• the skin over it changes, turns red or breaks down into a sore;
• a sebaceous cyst becomes red, swollen and filled with pus, especially if you also have a fever.

More often than not, these signs do not mean cancer, but they do mean the lump needs to be checked carefully.

At the appointment we ask when the lump appeared, whether it has grown and whether it bothers you, then we look at it and examine it by hand. This is often enough for an initial diagnosis. If you have earlier ultrasound results, bring them with you; the address and how to book are on the contact page.

• Ultrasound shows the size, depth and structure of the growth and helps tell a lipoma apart from a cyst or a lymph node.
• MRI may be needed for large, deep or unusual-looking growths.
• Histology: the tissue removed during surgery is examined under a microscope in a laboratory. This test confirms the final diagnosis.

Non-surgical (conservative) treatment

There is no ointment, cream, compress or “folk remedy” that dissolves a lipoma or a sebaceous cyst. These remedies waste time, and with a sebaceous cyst they can irritate the skin and cause inflammation. Some injections can shrink a lipoma temporarily, but the capsule stays in place and the growth often comes back; on top of that, the tissue is not examined under the microscope.

With an inflamed sebaceous cyst, the inflammation is calmed down first: antibiotics are prescribed when needed, and if pus has collected, the cyst is opened through a small incision and drained. The capsule is removed later, as a planned procedure, once the inflammation has fully settled. For a small lipoma without symptoms, treatment means regular monitoring.

Surgical and minimally invasive methods

Lipoma removal (excision). Small lipomas that lie just under the skin are usually removed under local anesthesia: you stay awake, and instead of pain you mostly feel touch or pressure in the area. The incision is kept as small as possible and made along the skin's natural lines so that the scar is less noticeable. The lipoma is removed completely, together with its capsule, and the wound is closed with cosmetic stitches. For very large lipomas or those that extend under a muscle, the type of anesthesia and the extent of surgery are chosen individually.

Sebaceous cyst removal. The cyst is removed together with its sac, along with a small patch of skin that includes the dark dot in the center. When the capsule is removed completely, the chance of the cyst coming back drops significantly.

For small growths, the procedure is often short and you go home the same day; the exact duration is given after the examination. If you have another surgical problem as well, we discuss at the consultation whether both can be treated in one session (combined “bouquet” surgery).

These are average timelines; your exact timeline is given after the examination. To keep the scar less noticeable, protect it from direct sun for the first few months; once the stitches are out, you can use a silicone gel or silicone patches on your doctor's advice. The scar softens and fades over several months. If you tend to form keloids (thick, raised scars), tell us before surgery.

There is no proven way to prevent lipomas. But these rules help you avoid complications and make the right decision in time:

1. Do not squeeze or pierce a sebaceous cyst. This can push infection deeper and make the cyst inflamed.
2. Do not waste time on ointments and compresses at home. They will not make the lump disappear.
3. Keep track of its size. If a lipoma is being monitored, measure it with a ruler from time to time and take a photo.
4. Do not wait if something changes. Fast growth, hardening or pain is a reason to get examined.
5. Take good care of your skin. For oily, acne-prone skin, regular gentle cleansing may lower the risk of sebaceous cysts.