Lipoma

What is a lipoma?

A lipoma is a benign growth made predominantly of mature fat cells. Most lipomas develop in the fatty layer just beneath the skin, although less commonly they may occur deeper within or between muscles.

They can occur almost anywhere on the body and are commonly noticed on the shoulders, upper limbs, back, trunk and thighs.

A typical superficial lipoma is soft or rubbery, moves to some extent beneath the skin and enlarges slowly. Most are painless.

Is a lipoma cancer?

A true lipoma is benign and is different from a liposarcoma, which is a malignant soft-tissue tumour.

Most soft, slowly growing superficial lumps are harmless, but not every lump that feels fatty is necessarily a lipoma. A rapidly enlarging, deep, firm or fixed lump, or one with other unusual features, deserves further assessment rather than being assumed to be a simple lipoma.

The purpose of appropriate examination and investigation is therefore not because ordinary lipomas commonly become malignant, but because occasionally another type of soft-tissue lesion can resemble a lipoma.

How is a lipoma diagnosed?

Many superficial lipomas have a characteristic appearance and feel and can be diagnosed clinically.

Ultrasound may be useful when the diagnosis is uncertain or when the lump is enlarging or has features that need further characterisation.

MRI or other imaging may be appropriate for large, deep, recurrent or atypical masses, particularly when the relationship with underlying muscles, nerves or other structures needs to be defined.

If imaging or clinical examination raises concern about a soft-tissue tumour, further assessment and an appropriately planned biopsy may be preferable to simply removing the lump without prior investigation.

Does every lipoma need to be removed?

No.

A small, typical and asymptomatic lipoma can usually be observed. There is no medical requirement to remove every lipoma.

Removal may be considered when the lump:

• causes pain or discomfort;
• interferes with movement, clothing or daily activity;
• appears to be increasing in size;
• causes pressure symptoms because of its location;
• is cosmetically troublesome to the patient; or
• needs removal or tissue diagnosis because the diagnosis remains uncertain.

The benefits of removing a harmless lump should always be balanced against the fact that surgery produces a scar and carries a small risk of complications.

How is a lipoma removed?

Most small superficial lipomas can be removed through a minor surgical procedure, often under local anaesthesia.

An incision is made over or close to the lump. The lipoma is carefully separated from the surrounding tissues and removed. Bleeding is controlled and the skin is closed, usually with sutures.

The size and position of the incision depend on the size, depth and location of the lipoma. Very large, deep or anatomically difficult lipomas may require a more extensive operation and sometimes general or regional anaesthesia.

The removed tissue is commonly sent for histopathological examination, particularly when confirmation of the diagnosis is appropriate.

Will there be a scar?

Yes. Any surgical removal of a lipoma requires an incision and therefore leaves a scar.

The surgeon usually plans the incision with consideration for the size and orientation of the lesion, skin creases and safe access to the lump. The final scar also depends on individual healing, the anatomical site, wound tension and the size and depth of the lesion.

A very large lipoma may require a longer incision than patients initially expect because safe removal through an excessively small opening may cause unnecessary tissue trauma.

Can a lipoma come back after removal?

Recurrence after complete removal of an ordinary superficial lipoma is uncommon, but it can occur.

A lump appearing again at the same site should be reassessed, particularly if it grows rapidly or behaves differently from the original lesion.

Some people naturally develop multiple lipomas at different sites. A new lipoma elsewhere does not mean that a previously removed lipoma has spread.

What happens after surgery?

Most straightforward superficial lipoma excisions are day-care procedures.

Patients usually go home after a short period of observation. Pain is generally manageable with simple analgesia. The wound should be kept and dressed according to the instructions provided.

Depending on the site and size of the excision, strenuous activity or movements that place significant tension on the wound may need to be limited temporarily.

If non-absorbable sutures have been used, they are removed according to the anatomical site and wound healing.

When should a lump be assessed promptly?

Medical assessment is particularly important if a lump:

• is increasing noticeably in size;
• becomes hard or fixed rather than mobile;
• appears to lie deep to the superficial tissues;
• causes persistent or unexplained pain;
• causes weakness, numbness or other pressure symptoms;
• has recurred after previous removal; or
• has an uncertain diagnosis.

After surgery, increasing redness, swelling, discharge, fever, worsening pain or significant bleeding should prompt medical review.

This information is intended for general patient education and does not replace examination or individual medical advice.