A lipoma is a benign growth of fat beneath the skin. It is one of the most common causes of a soft, mobile lump and often develops on the shoulders, back, arms, thighs or trunk. Most lipomas are harmless and grow slowly, but not every soft-tissue mass is a lipoma. Assessment is recommended when a lump is new, enlarging, painful, deep or has unusual features.

Typical features of a lipoma

Lipomas usually feel soft or rubbery and move slightly when pressed. They are often painless, although discomfort can occur if a lump presses on a nerve or sits in an area exposed to friction. Some people have several lipomas. A firm, fixed, rapidly growing or deep mass is less typical and requires further investigation.

Could the lump be something else?

Skin cysts, enlarged lymph nodes, benign nerve or connective-tissue tumours and inflamed tissue may resemble a lipoma. Rarely, a soft-tissue mass can be malignant. Features prompting urgent investigation include rapid growth, a size greater than about 5 cm, deep fixation, significant pain or recurrence after removal.

Diagnosis and imaging

Your surgeon will assess the lump’s size, depth, mobility and location. Ultrasound often helps distinguish a superficial fatty mass from a cyst. MRI may be recommended for a large, deep, fixed or uncertain lesion. If the findings are concerning, referral to a specialist soft-tissue tumour service may be more appropriate than routine removal. Histology provides the definitive diagnosis after biopsy or excision.

Treatment

A small, asymptomatic lipoma can often be observed. Removal may be considered if it is painful, growing, restricting movement or causing concern. Excision is commonly performed through an incision over the lump under local or general anaesthesia depending on its size and depth. The tissue is sent for analysis.

Risks of removal

Risks include bleeding, infection, fluid collection, numbness, contour change, scarring and recurrence. Larger or deeper masses may be close to nerves or blood vessels and require more extensive surgery.

Frequently asked questions

Can a lipoma become cancerous? A typical lipoma does not usually transform into cancer, but an atypical mass may need imaging or biopsy to confirm the diagnosis.

Does every lipoma need removal? No. Many can be safely monitored.

Can a lipoma return after surgery? Recurrence is uncommon after complete excision but can occur. the balance of risks and benefits.

Will previous mesh need to be removed? Not usually. Removal is considered only when clinically necessary.