Lipoma

Overview

•Soft, doughy consistency - hallmark feature, like soft putty beneath the skin

•Freely mobile - slides beneath the examining finger; overlying skin moves freely

•Well-defined edges - smooth, distinct border from fibrous capsule

•Normal overlying skin - no erythema, punctum, or tethering (distinguishes from epidermoid cyst)

•Non-tender - tenderness suggests angiolipoma or nerve compression

•Size - typically 0.5-10 cm; ~80% under 5 cm

•Multiple lipomas - minority of patients; consider underlying syndrome (Gardner, Dercum, Madelung disease)

💡

Angiolipoma - variant with vascular component; can be painful/tender unlike typical lipoma.

Investigations

🥇 First-line

•Clinical assessment alone - sufficient for typical soft, mobile, doughy, well-circumscribed superficial lump

•First-line (imaging): Ultrasound - initial modality where diagnostic uncertainty exists; confirms subcutaneous location

🏆 Gold standard

•MRI - modality of choice for deeper or atypical lesions; distinguishes lipoma from liposarcoma; assesses depth and fascial relationship

🥈 Second-line

•CT scan - alternative to MRI, useful for deep or retroperitoneal lesions

•Biopsy - reserved for atypical imaging features or high suspicion of liposarcoma

Management

🥇 First-line

•Conservative management (watchful waiting) - for small, asymptomatic, superficial lipomas with confident clinical diagnosis; reassure and advise return if rapid growth, pain, or change in character

🥈 Second-line

•Surgical excision - indicated for cosmetic concern, compressive symptoms, diagnostic uncertainty, or continued growth; excise with capsule intact to minimise recurrence

•Minimal excision or liposuction - alternative for superficial lipomas; lower scarring risk but higher recurrence rate than formal excision

🥉 Third-line

•Urgent specialist referral (sarcoma/plastic surgery) - any red flag features; excision biopsy considered

Complications

•Nerve or vascular compression - pain, paraesthesia, or rarely vascular compromise in confined anatomical spaces

•Recurrence post-excision - uncommon after formal excision with intact capsule; higher with liposuction or minimal excision

•Diagnostic delay of liposarcoma - greatest clinical risk; well-differentiated liposarcoma may be misdiagnosed as benign lipoma

Red flags for liposarcoma

Features raising concern for liposarcoma

Size >5 cm, especially thigh or retroperitoneum

Deep to or fixed to fascia

Rapid growth over weeks to months

Firm or hard consistency

Pain not explained by nerve compression

Invasion into adjacent bone or nerve on imaging

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Thigh lipoma >5 cm should be referred for specialist opinion to exclude liposarcoma even if clinically benign - well-differentiated liposarcoma can be indistinguishable on examination alone.