What is the best course of treatment for a 62-year-old female patient with malignant melanoma of the left lower limb, who recently underwent sclerotherapy for a seroma and is experiencing pain and swelling?

Management of Post-Surgical Seroma in Melanoma Patient

Continue conservative management with compression therapy, limb elevation, and close monitoring rather than repeated sclerotherapy, as the evidence does not support sclerotherapy for seroma treatment and the patient is already on pembrolizumab which requires careful infection surveillance.

Primary Management Strategy

The current clinical scenario involves a postoperative complication (seroma) in a patient receiving systemic immunotherapy for melanoma. The focus should be on conservative measures that minimize infection risk and support wound healing while continuing oncologic treatment.

Conservative Compression-Based Approach

• Compression wraps remain the cornerstone of seroma management and should be continued as currently prescribed, with adjustable compression devices showing equivalent efficacy to traditional multilayer bandaging for reducing fluid accumulation 1
• Limb elevation while sitting or lying down should be maintained as part of the current plan to reduce hydrostatic pressure and promote lymphatic drainage 2
• Early mobilization with compression is superior to bed rest for managing lower extremity fluid collections, promoting faster resolution of swelling and pain 3

Sclerotherapy Considerations

• Sclerotherapy for seromas lacks established efficacy in the medical literature, and the insurance determination correctly identifies insufficient evidence for this indication 4
• The patient has already undergone one sclerotherapy session (10/20/2025) with alcohol, yet continues to experience pain and fluid reaccumulation, suggesting limited benefit from this intervention
• Repeated invasive procedures increase infection risk, which is particularly concerning given this patient's immunotherapy status

Critical Safety Considerations with Pembrolizumab

Infection Risk with PD-1 Inhibition

• Pembrolizumab significantly increases susceptibility to severe infections, particularly tuberculosis and other bacterial infections, as PD-1 blockade impairs normal immune responses to pathogens 5
• Animal studies demonstrate that PD-1 knockout mice exhibit markedly decreased survival with bacterial infections due to enhanced inflammatory responses 5
• This patient has already experienced one episode of possible seroma infection (10/15/25) requiring antibiotics, indicating heightened vulnerability

Monitoring Requirements

• Close surveillance for signs of infection is mandatory: erythema, warmth, purulent drainage, fever, or systemic symptoms should prompt immediate evaluation 6
• The current physical exam showing "no significant erythema or palpable warmth" is reassuring and supports continued conservative management
• Avoid unnecessary invasive procedures that create additional portals for bacterial entry in immunotherapy patients 6

Melanoma-Specific Management

Systemic Treatment Priority

• Pembrolizumab should not be interrupted for seroma management unless there is active infection, as maintaining immunotherapy continuity is critical for melanoma control in this patient with concerning PET findings (metabolically active lymph nodes) 7
• The patient's melanoma treatment takes precedence over the seroma, which is a self-limited complication that typically resolves with conservative measures 4

Surgical Site Healing

• The incision is described as "well-approximated, c/d/l" indicating appropriate healing despite the seroma 6
• Seromas after wide local excision and sentinel lymph node biopsy are common due to the anatomical dead space created, particularly in the groin region 4

Recommended Treatment Algorithm

1. Continue current compression therapy with wraps, ensuring proper technique and adequate pressure (20-30 mmHg for maintenance) 8, 1
2. Maintain limb elevation whenever possible to reduce hydrostatic pressure 2
3. Encourage ambulation with compression rather than bed rest, as mobilization promotes resolution 3
4. Monitor weekly for volume changes, signs of infection, and patient comfort rather than scheduling routine repeat sclerotherapy 6
5. Consider aspiration only if the seroma becomes tense, painful, or shows signs of infection—but avoid routine sclerotherapy given lack of evidence 4
6. Continue pembrolizumab without interruption unless active infection develops 7, 5

Pain Management

• The patient's pain is likely related to tissue tension from fluid reaccumulation rather than infection (given normal exam findings)
• Ice or heat application for 20 minutes as currently prescribed is appropriate for symptomatic relief
• Analgesics (acetaminophen or NSAIDs if not contraindicated) can be used for comfort
• Pain should improve as seroma volume decreases with compression therapy 3

Common Pitfalls to Avoid

• Do not pursue repeated sclerotherapy without evidence of benefit, as this increases infection risk in an immunocompromised patient 4, 5
• Do not delay or interrupt pembrolizumab for seroma management unless active infection is present, as melanoma control is the priority outcome for mortality 7
• Do not rely on bed rest, as this worsens venous stasis and delays seroma resolution 3
• Do not ignore subtle signs of infection in patients on PD-1 inhibitors, as these patients can develop severe infections rapidly 6, 5