What is the cause of swelling in the axilla after breast surgery?

Axillary Swelling After Breast Surgery

The most common cause of axillary swelling after breast surgery is lymphedema, which occurs in 3-25% of patients following axillary lymph node dissection, with significantly lower rates (below 10%) after sentinel lymph node biopsy alone. 1

Primary Causes of Axillary Swelling

Lymphedema (Most Common)

• Lymphedema results from interruption or obstruction of lymphatic vessels during axillary surgery, causing fluid accumulation in the upper limb and axilla. 1, 2
• The incidence varies significantly based on the extent of axillary surgery:
  • 3-5% after axillary clearance alone 1
  • Up to 25% following axillary lymph node dissection 1
  • Below 10% after sentinel lymph node biopsy only 1
  • 40% when axillary clearance is combined with axillary radiotherapy 1
• The mean time from surgery to lymphedema development is approximately 479 days (range: immediate to >1 year). 2

Seroma Formation

• Seroma is a common postoperative complication related to both breast and axillary surgery, presenting as fluid collection in the surgical bed. 3

Accessory Breast Tissue

• Accessory axillary breast tissue (present in 2-6% of women) can cause axillary swelling that mimics lymphadenopathy, particularly during hormonal changes, pregnancy, or postoperatively. 4, 5
• This tissue undergoes premenstrual changes including tenderness and swelling. 5

Post-Surgical Inflammatory Changes

• Erythema and edema can occur after breast or axillary surgery due to lymphatic vessel interruption, mimicking infectious mastitis or inflammatory breast cancer. 6
• This syndrome typically resolves spontaneously within 2 months to 1 year without specific treatment. 6

Other Causes

• Infection (requiring immediate antibiotic treatment) 1, 3
• Hematoma 3
• Fat necrosis 3

Risk Factors for Lymphedema Development

Key risk factors that significantly increase lymphedema risk include: 2

• Dissection of >18 axillary lymph nodes 2
• Radiotherapy to the axilla 1, 2
• Smoking 2
• Body mass index >26 kg/m² 2
• Obesity 7

Diagnostic Approach

Clinical Evaluation

• Lymphedema is defined as symptomatic arm swelling with >2 cm difference in arm circumference between affected and contralateral arms. 2
• Arm circumference measurements alone correlate poorly with volume differences; volume determination is more accurate. 8
• For axillary masses that may represent accessory breast tissue, perform age-appropriate imaging: ultrasound with mammogram for patients ≥30 years, ultrasound alone for patients <30 years. 4
• Core needle biopsy is indicated for palpable axillary masses appearing suspicious on imaging. 4

Differential Diagnosis Considerations

• Rule out infection (requires immediate antibiotics) 1
• Exclude malignancy or recurrence 4
• Consider accessory breast tissue if swelling mimics lymphadenopathy 4
• Evaluate for post-surgical inflammatory changes if erythema and edema are present 6

Management Algorithm

For Suspected Lymphedema:

1. Immediate referral to a lymphedema specialist (physical therapist, occupational therapist, or lymphedema specialist) for patients with clinical symptoms or suggestive swelling 7
2. Initiate treatment with compression bandaging, manual lymphatic drainage, and graduated compression garments 1
3. Implement supervised progressive resistance training, which is safe and effective for reducing lymphedema risk 7
4. Treat any infections immediately with antibiotics to prevent worsening 1, 7
5. Recommend weight loss for patients with overweight or obesity 7

For Accessory Breast Tissue:

• Observation is acceptable for asymptomatic patients not bothered by the condition 4
• Surgical removal is recommended for symptomatic patients experiencing premenstrual changes, pain, or cosmetic concerns 4, 5

For Post-Surgical Inflammatory Changes:

• Recognize that antibiotic therapy is generally ineffective 6
• Expect spontaneous resolution with time (2 months to 1 year) 6

Critical Pitfalls to Avoid

• Do NOT advise patients to avoid all physical activity and weight lifting with the affected arm—this outdated recommendation is contraindicated; supervised progressive resistance training is safe and beneficial. 7
• Do NOT use diuréticos for lymphedema management—they are generally ineffective. 7
• Do NOT delay treatment, as this leads to lymphedema progression and increased complication risk. 7
• Do NOT assume all axillary swelling is lymphedema—consider accessory breast tissue, seroma, infection, and post-surgical inflammatory changes in the differential. 4, 6, 3
• Do NOT advise patients to avoid cannulation, venesection, or blood pressure monitoring in the ipsilateral arm after axillary clearance. 1