What is the best treatment approach for a patient with lipomas in both flanks?

Management of Lipomas in Both Flanks

The best treatment approach for lipomas in both flanks is surgical excision through complete en bloc resection, preserving adjacent neurovascular structures without attempting wide surgical margins. 1

Diagnostic Approach

Before proceeding with treatment, proper diagnosis is essential:

• Initial evaluation should include ultrasound as an effective triage tool to determine if the masses are indeed lipomas 1
• If the ultrasound confirms lipomatous appearance but there is diagnostic uncertainty, MRI should be performed 1
• MRI with expert review can differentiate between benign lipomas and atypical lipomatous tumors (ALT) in up to 69% of cases 1
• For definitive diagnosis in cases of uncertainty, percutaneous core needle biopsy to analyze for MDM-2 amplification should be performed 1

Treatment Options

Surgical Management (Primary Approach)

• Complete en bloc surgical excision is the standard treatment for symptomatic lipomas 1
• Marginal resections as a complete en bloc specimen will give excellent rates of long-term local control 1
• The "one-inch method" is a minimally invasive technique for resecting large subcutaneous lipomas through a small incision after blunt dissection 2
• Surgical time may vary based on location - flank/torso lipomas may require longer operative times than those on extremities due to more retaining ligaments 2

Non-Surgical Management

• For asymptomatic, small lipomas or in patients with significant comorbidities, observation with radiological surveillance can be considered 1
• In older patients where surgery might be morbid, watchful waiting is a reasonable approach 1

Special Considerations

Distinguishing Between Lipoma and Atypical Lipomatous Tumor (ALT)

• ALT/well-differentiated liposarcoma tends to be larger, deep-seated, and more common in the lower limb 1
• MRI features suggesting ALT include nodularity, septations, stranding, and larger relative size 1
• The definitive diagnostic test is molecular demonstration of MDM-2 cell cycle oncogene amplification by fluorescence in-situ hybridization 1

Red Flags Requiring Urgent Referral

• Consider urgent referral if the lipoma is:
  • Rapidly increasing in size 1
  • Larger than 5 cm 1
  • Deep-seated 1
  • Painful 1
  • Shows concerning features on imaging 1

Post-Treatment Follow-up

• Following surgical excision and post-operative wound care, patients can be discharged to primary care 1
• Re-referral is only necessary if there is clinical suspicion of recurrence 1
• Recurrence rates for properly excised lipomas are low 1

Common Pitfalls and Caveats

• Failure to distinguish between benign lipoma and atypical lipomatous tumor can lead to inadequate treatment 1
• Incomplete excision may result in recurrence, particularly with ALTs 1
• For large lipomas or those where clear margins are difficult to achieve, adjuvant radiotherapy may occasionally be considered, though this is rare for typical lipomas 1
• Lipomas must be distinguished from liposarcoma, which can have a similar appearance but requires more aggressive management 3