Lipomas are slow-growing, benign, mesenchymal tumours that form well-circumscribed, lobulated lesions composed of adipocytes.

They are demarcated from surrounding fat by a thin, fibrous capsule.

They comprise 50% of soft-tissue neoplasms and are commonly encountered by primary care physicians, surgeons, and pathologists

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

Risk factors:

• Genetic predisposition
• Weak R/F: Trauma and alcohol

PC

• A soft, smooth cutaneous mass <5cm in diameter (?malignant if >5)
  • mobile and well circumscribed
  • superficial
  • painless
• Normal coloured skin

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.

Investigations

*Usually a clinical diagnosis

Consider:

• imaging if lesion is >3cm and seeps deep to superficial fascia
• Core needle biopsy - for any soft tissue mass that is symptomatic or enlarging >3cm
• CNB inconclusive - consider incisional or exitional biopsy