First-Line Treatment for Left Axillary Cyst
For a simple axillary cyst, the first-line treatment is observation with reassurance if asymptomatic, or aspiration/drainage if the cyst is causing symptoms or discomfort. 1
Initial Diagnostic Approach
The evaluation begins with determining whether this represents a true simple cyst versus other pathology:
- Age-appropriate imaging is essential: For patients ≥30 years, obtain ultrasound with mammogram; for patients <30 years, ultrasound alone is sufficient 1, 2
- Clinical evaluation must assess for other sites of adenopathy and potential non-breast etiologies, as axillary masses can represent accessory breast tissue, lymphadenopathy, or true dermal cysts 1, 2
- Ultrasound characteristics of benign epidermal inclusion cysts include an oval-shaped hypoechoic subcutaneous mass with dermal attachment, intralesional echogenic reflectors, and no vascularity 3
Management Based on Imaging Findings
For Simple Cysts (BI-RADS Category 2)
- If asymptomatic and confirmed benign on imaging: Observation is acceptable with reassurance to the patient 1, 2
- If symptomatic (causing focal pain or discomfort): Drainage may be considered for symptom relief 1
- No further intervention is required for asymptomatic simple cysts that are clearly benign on imaging 1
For Complicated Cysts (BI-RADS Category 3)
- Appropriate imaging follow-up every 6 months for 1-2 years is recommended along with symptomatic management if desired 1
For Suspicious Lesions (BI-RADS Category 4 or 5)
- Core needle biopsy is mandatory for any palpable axillary mass that appears suspicious or highly suggestive of malignancy on imaging 1, 2
- Surgical excision becomes necessary if malignancy is confirmed 1
Surgical Excision Considerations
Complete surgical excision is reserved for specific scenarios:
- Large or growing cysts causing discomfort due to size, as these can cause complications from their location in the axilla 3, 4
- Recurrent cysts after aspiration, as complete excision is the definitive treatment with the highest cure rate (95%) compared to aspiration alone (39%) 5
- Any concern for malignancy based on imaging characteristics or clinical suspicion 1, 2
- Ruptured or infected cysts, as rupture can cause pain and infection requiring definitive treatment 4
Critical Pitfalls to Avoid
- Never assume a palpable axillary mass is benign without appropriate imaging, especially in patients with risk factors for breast cancer, as accessory breast tissue in the axilla can harbor malignancy 6
- Do not perform surgical excision as first-line treatment for clearly benign, asymptomatic simple cysts confirmed on ultrasound 1
- Ensure adequate tissue sampling if biopsy is performed, obtaining sufficient material for both histology and receptor testing if malignancy is suspected 7
- Recognize that multiple bilateral axillary cysts may suggest underlying syndromes, though isolated unilateral cysts are typically benign epidermal inclusion cysts 4