What is the treatment for a cyst in the axilla?

Treatment of Axillary Cysts

For a simple cyst in the axilla, drainage may be considered for symptom relief, while complicated cysts require appropriate imaging follow-up every 6 months for 1-2 years, and suspicious cysts should undergo core needle biopsy. 1

Diagnostic Approach

Initial Evaluation

• Complete clinical evaluation to assess for other sites of adenopathy and potential non-breast etiologies
• Age-appropriate diagnostic imaging:
  • Ultrasound with mammogram for patients ≥30 years
  • Ultrasound alone for patients <30 years 1

Imaging Classification

Based on imaging findings, axillary cysts are categorized as:

1. Simple cyst (BI-RADS category 2): Benign appearance
2. Complicated cyst (BI-RADS category 3): Probably benign
3. Suspicious cyst (BI-RADS category 4-5): Requires tissue sampling 1

Treatment Algorithm

Simple Cysts (BI-RADS 2)

• If asymptomatic: Observation
• If symptomatic (focal pain): Drainage may be considered for symptom relief
• Minimal incision techniques using negative-pressure suction can be effective for larger cysts (>2 cm) 1, 2

Complicated Cysts (BI-RADS 3)

• Appropriate imaging follow-up every 6 months for 1-2 years
• Symptomatic management of associated pain if present
• Consider drainage if symptomatic 1

Suspicious Cysts (BI-RADS 4-5)

• Core needle biopsy is the preferred option
• Surgical excision is an alternative option
• If biopsy shows malignancy, follow appropriate cancer management protocols 1

Special Considerations

Differential Diagnosis

It's important to consider that axillary masses may represent:

• Epidermal inclusion cysts (most common benign cysts in axilla) 2, 3
• Bursal cysts (rare in axilla) 4
• Ectopic breast tissue or malignancy (may initially appear as a sebaceous cyst) 5
• Lymphadenopathy from various causes 1

Surgical Approaches

When surgical excision is indicated:

• Minimal incision techniques (0.7-1.8 cm) with negative-pressure suction can be effective for large cysts
• This approach minimizes scarring and reduces risk of cyst rupture compared to traditional lateral pressure techniques 2
• For cosmetically sensitive cases, endoscopic approaches through remote incisions (e.g., mammary areolae and axilla) can be considered 6

Pitfalls and Caveats

• Axillary masses initially diagnosed as benign cysts may occasionally be malignant, particularly in patients with risk factors for breast cancer 5
• Lateral pressure during manual extraction can cause unintended rupture and fragmentation of the cyst lining, potentially leading to infection and recurrence 2
• Calcifications within axillary cysts may be confused with malignancy on imaging 3
• Always consider the possibility of occult breast cancer when evaluating axillary masses, particularly in patients with risk factors 1, 5

By following this structured approach to axillary cysts, appropriate treatment can be provided based on imaging characteristics and clinical presentation, minimizing both unnecessary procedures and the risk of missing significant pathology.