Lipoma

Introduction | Aetiology and Risk Factors | Clinical Presentation | Diagnosis | Management and Treatment | When to Refer | References

Introduction

Lipomas are benign soft tissue tumours composed of mature adipose tissue. They are the most common type of soft tissue tumour and typically present as soft, movable, and painless lumps beneath the skin. Lipomas are generally slow-growing and are most often found in adults. Although they are benign, they can sometimes cause discomfort or cosmetic concerns, prompting individuals to seek medical attention.

Aetiology and Risk Factors

The exact cause of lipoma development is not well understood, but several factors may contribute to their formation:

• Genetics: A family history of lipomas may increase the likelihood of developing these tumours, suggesting a genetic predisposition.
• Age: Lipomas most commonly occur in middle-aged and older adults, although they can develop at any age.
• Trauma: Some lipomas have been reported to develop at the site of an injury, although this is not a consistent finding.
• Obesity: While lipomas are composed of fat tissue, there is no direct correlation between lipoma development and obesity.
• Medical Conditions: Certain conditions, such as familial multiple lipomatosis, Gardner syndrome, and Madelung's disease, are associated with the development of multiple lipomas.

Clinical Presentation

Lipomas typically present with the following characteristics:

• Soft, Painless Lump: The most common presentation is a soft, doughy, and movable lump beneath the skin. Lipomas are usually painless unless they compress nearby nerves or tissues.
• Size and Growth: Lipomas can range in size from a few millimetres to several centimetres in diameter. They tend to grow slowly over time.
• Location: Lipomas can develop anywhere on the body but are most commonly found on the upper back, shoulders, abdomen, arms, and thighs.
• Shape and Consistency: They are typically round or oval and have a soft, rubbery consistency. They are usually well-defined and move easily under the skin when pressed.
• Multiple Lipomas: Some individuals may develop multiple lipomas, particularly those with a genetic predisposition.

Diagnosis

The diagnosis of a lipoma is usually clinical, based on the characteristic appearance and feel of the lump. However, additional investigations may be necessary in certain situations:

• Clinical Examination: A thorough physical examination is typically sufficient for diagnosing a lipoma. The lump's softness, mobility, and lack of tenderness are key features.
• Imaging:
  • Ultrasound: An ultrasound can be used to confirm the diagnosis, particularly if the lipoma is deep-seated or if the diagnosis is uncertain. It can differentiate a lipoma from other soft tissue masses.
  • MRI: MRI may be indicated if the lipoma is large, deep, or causing symptoms, as it provides detailed information about the tumour's size, depth, and relationship to surrounding structures.
• Biopsy: A biopsy may be performed if there is uncertainty about the diagnosis, particularly if the lipoma has atypical features, such as rapid growth, pain, or firmness. The biopsy helps rule out liposarcoma, a rare malignant tumour that can resemble a lipoma.

Management and Treatment

Management of lipomas is often conservative, but treatment may be considered for symptomatic or cosmetically concerning lesions:

1. Observation

• As lipomas are benign and typically asymptomatic, many do not require treatment. Patients can be reassured and monitored if the lipoma is not causing any issues.

2. Surgical Removal

• Indications for Surgery: Surgical removal may be indicated if the lipoma is painful, rapidly growing, cosmetically undesirable, or causing functional impairment due to its location.
• Procedure: The surgery is usually performed under local anaesthesia as an outpatient procedure. The entire lipoma, including its capsule, is excised to prevent recurrence.
• Complications: Surgery is generally low-risk, but potential complications include infection, scarring, and recurrence if the lipoma is not completely removed.

3. Liposuction

• Liposuction is a less invasive option for removing larger lipomas. However, it may be less effective in ensuring complete removal, which could lead to recurrence.

4. Monitoring

• For lipomas that are not removed, regular monitoring is recommended to observe any changes in size, shape, or symptoms that might warrant further investigation or treatment.

When to Refer

Referral to a specialist, such as a dermatologist or surgeon, may be necessary in the following situations:

• Uncertain Diagnosis: If there is any doubt about the diagnosis, especially if the lipoma has atypical features (e.g., rapid growth, pain, firmness), referral for further evaluation is recommended.
• Large or Deep Lipomas: Lipomas that are large, deep, or located near vital structures may require specialist assessment and surgical planning.
• Recurrent Lipomas: If a lipoma recurs after removal, referral to a specialist may be necessary to ensure complete excision and to rule out other underlying conditions.
• Multiple Lipomas: Patients with multiple lipomas, particularly if associated with genetic syndromes, may benefit from referral for genetic counselling and further evaluation.

References

1. British Association of Dermatologists (2024) Guidelines for the Management of Lipomas. Available at: https://www.bad.org.uk (Accessed: 26 August 2024).
2. National Institute for Health and Care Excellence (2024) Lipoma: Diagnosis and Management. Available at: https://www.nice.org.uk/guidance/ng109 (Accessed: 26 August 2024).
3. British National Formulary (2024) Management of Benign Soft Tissue Tumours. Available at: https://bnf.nice.org.uk/ (Accessed: 26 August 2024).