Axillary Swelling After Breast Surgery

Primary Causes of Axillary Swelling

The American Society of Clinical Oncology notes that lymphedema results from interruption or obstruction of lymphatic vessels during axillary surgery, causing fluid accumulation in the upper limb and axilla 1
The incidence of lymphedema varies significantly based on the extent of axillary surgery, with rates of 3-5% after axillary clearance alone, up to 25% following axillary lymph node dissection, and below 10% after sentinel lymph node biopsy only 2, 3, 1
The combination of axillary clearance and axillary radiotherapy increases the risk of lymphedema to 40% 2, 3, 1
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

Radiotherapy to the axilla is a significant risk factor for lymphedema development 2, 1
Obesity, with a body mass index >26 kg/m², is also a risk factor for lymphedema 5

For axillary masses that may represent accessory breast tissue, the American College of Radiology recommends performing 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

The National Comprehensive Cancer Network recommends immediate referral to a lymphedema specialist for patients with clinical symptoms or suggestive swelling 5
Initiate treatment with compression bandaging, manual lymphatic drainage, and graduated compression garments 1
Supervised progressive resistance training is safe and effective for reducing lymphedema risk 5
Treat any infections immediately with antibiotics to prevent worsening 1, 5
Recommend weight loss for patients with overweight or obesity 5

The American Cancer Society advises against advising patients to avoid all physical activity and weight lifting with the affected arm, as supervised progressive resistance training is safe and beneficial 5
Do not use diuretics for lymphedema management, as they are generally ineffective 5
Delaying treatment leads to lymphedema progression and increased complication risk 5
Consider accessory breast tissue, seroma, infection, and post-surgical inflammatory changes in the differential diagnosis of axillary swelling 4

In patients who undergo sentinel lymph node biopsy (SLNB), the majority of axillary surgical adverse effects improve markedly within the first 3 months after surgery; however, 5‑10 % of these patients continue to report persistent severe sensory disturbances beyond this period. 6

Axillary web syndrome—characterized by tender, cord‑like lymphatic structures along the upper inner arm—can occur as a temporary complication following SLNB. 6

Seroma formation is identified as the most common early‑post‑operative axillary complication after breast‑conserving surgery with SLNB. 6