Lipoma

Question 1

Define lipoma.

Answer 1

Lipomas are slow-growing, benign, mesenchymal tumours that form well-circumscribed, lobulated lesions composed of adipose tissue. They are demarcated from surrounding fat by a thin, fibrous capsule.

Usually arise in the subcutaneous tissue.

Question 2

How common are lipomas?

Answer 2

1% of the population has a lipoma

Occur at any age but most common between 40-60yrs

Congenital lipomas found in some children

Question 3

Where do lipomas usually occur on the body?

Answer 3

Lipomas usually arise in the subcutaneous tissues and may occur in any area of the body, although they most frequently occur on the trunk and proximal limbs.

Question 4

Can lipomas turn cancerous?

Answer 4

They have no malignant potential, but the differential diagnosis includes liposarcomas, which do have this potential, so this must always be considered.

Question 5

What is the aetiology of lipomas?

Answer 5

• Idiopathic (trauma may also be a cause)
• Hereditary - familial multiple lipomatosis or Gardner’s syndrome

Syndromes which cause lipomas:

• Madelung’s disease - benign symmetric lipomatosis of the head, neck, shoulders and proximal upper extremities; associated with men with heavy alcohol consumption
• Dercum’s disease - adiposis dolorosa ; in middle aged women and causes painful lipomas on the trunk, shoulders, arms and legs; aetiology unknown
• Bannayan-Riley-Ruvalcaba syndrome
• Proteus syndrome
• Multiple endocrine neiplasma

Question 6

What are the clinical features of a lipoma?

Answer 6

• superficial, round, mobile, soft (doughy)
• if fixed or tethered to underlying fascia then may be liposarcoma
• feels similar to subcutaneous fat
• truncal/extremity lipomas are <5cm in diameter; liposarcomas present at size >5cm but definitive diagnosis depends on histological confirmation
• painless

Question 7

What investigations would you do for a lipoma?

Answer 7

CT/MRI - consider if a lesion is more > 3 cm in diameter, appears clinically to be deep to the superficial fascia, and has a solid component = should show discrete, encapsulated, homogeneous mass, with few or no thin, discrete septa; density similar to normal fat

Excisional biopsy is recommended for cutaneous or subcutaneous tumours smaller than 3 cm that are growing, are symptomatic (e.g., causing pain or pressure effects), or seem to have a solid component more firm than subcutaneous fat

Question 8

What are the management options for a lipoma?

Answer 8

1. Observation - 1st line
2. Surgical excision - if they become painful or bothersome or for cosmetic reasons or suspicion of liposarcoma. But they may recur. Done under local anaesthesia.
3. Liposuction - less scarring but higher recurrence and incomplete sample for histopathology
4. Lipolysis for small lipomas <2.5cm - injection of corticosteroids or phosphatidylcholine may be used to trigger lipolysis

Question 9

Other than subcutaneous tissue, where else might lipomas occur?

Answer 9

• Oesophagus
• Stomach - shown below in gastric antrum
• Small intestine
• Rarely: adrenals, parotids, breast, mediastinum, pleura, major airway, heart, SVC, brain, intraspinal areas.

Submucosally; may present with obstruction or bleeding.

Question 10

What are the complications of lipomas?

Answer 10

Treatment-related:

• Wound infection
• Seroma
• Haematoma/ecchymosis
• Nerve injury
• Vascular compromise
• Keloid or hypertrophic scarring

Question 11

What is the prognosis with lipomas?

Answer 11

Slowly increase in size or remain static

1-2% recurrence rate

Lesions treated with liposuction and lipolysis have a higher recurrence rates due to incomplete removal of the original lesion.