Management of Axillary Sebaceous/Inclusion Cysts
Incision and drainage is the definitive treatment for inflamed axillary epidermoid (inclusion) cysts, and routine Gram stain, culture, or antibiotics are not recommended for uncomplicated cases. 1
Initial Assessment and Diagnosis
Clinical Evaluation
- Axillary masses require evaluation to distinguish between epidermoid cysts, lymphadenopathy, accessory breast tissue, or other soft tissue abnormalities 1
- Look specifically for: firm skin-colored nodules, dermal attachment, and absence of systemic adenopathy 2, 3
- Do not assume benignity based on palpation alone—physical examination cannot reliably distinguish benign cysts from malignancies 4
Imaging When Indicated
- Age-appropriate diagnostic imaging is recommended for axillary masses: ultrasound with mammogram for patients ≥30 years; ultrasound alone for patients <30 years 1
- Ultrasound typically shows: oval-shaped hypoechoic subcutaneous mass with dermal attachment, intralesional echogenic reflectors, and no vascularity 3
- Imaging helps differentiate epidermoid cysts from lymph nodes, particularly when axillary scarring makes clinical evaluation difficult 1
Treatment Algorithm
For Uninflamed/Asymptomatic Cysts
- Observation is acceptable for small, asymptomatic cysts 5
- Elective excision can be performed using minimal excision technique: 2-3 mm incision, expression of contents, and extraction of cyst wall without suture closure 6
- Complete excision is recommended if the cyst is large, growing, causing discomfort, or if there is concern for malignant transformation 2, 3, 7
For Inflamed Cysts
- Incision and drainage is the primary treatment (strong recommendation, high-quality evidence) 1
- Technique: make adequate incision, thoroughly evacuate contents, probe to break up loculations, apply dry dressing 5
- Do NOT obtain Gram stain or culture from inflamed epidermoid cysts (strong recommendation, moderate-quality evidence) 1
- Do NOT prescribe routine antibiotics—inflammation typically results from cyst wall rupture and keratin extrusion into dermis, not true bacterial infection 1, 5
When Antibiotics ARE Indicated
Systemic antibiotics directed against S. aureus should be reserved ONLY for: 1, 5
- Multiple lesions requiring coordinated management
- Cutaneous gangrene complicating the cyst
- Severely impaired host defenses (immunocompromised patients)
- Extensive surrounding cellulitis (>5 cm erythema with induration)
- Severe systemic manifestations (fever ≥38°C, sepsis)
Surgical Referral Criteria
Refer to general surgery when: 5
- Multiple lesions requiring coordinated surgical planning
- Cutaneous gangrene present
- Severely impaired host defenses
- Extensive surrounding cellulitis despite initial management
- Severe systemic manifestations including high fever or sepsis
Critical Pitfalls to Avoid
Common Misconceptions
- "Sebaceous cyst" is a misnomer—these are epidermoid cysts containing keratinous material, not sebaceous material 5
- Do not refer routine inflamed epidermoid cysts assuming they require antibiotics or specialized care 5
- Inflamed cysts are difficult to excise; postpone definitive excision until inflammation subsides 6
Malignancy Considerations
- While rare, malignant transformation to squamous cell carcinoma can occur, particularly in older patients or long-standing lesions 7
- Red flags requiring biopsy: rapid growth, fixation to deep structures, ulceration of overlying skin, firm consistency with indistinct borders, or lesions >1.5 cm that persist >2 weeks 1, 4
- All surgically excised cysts should undergo histologic evaluation if there are unusual findings or clinical suspicion of malignancy 7, 6
Special Axillary Considerations
- Multiple bilateral axillary epidermoid cysts, while rare, can occur without underlying syndrome or prior surgery 2
- Giant axillary cysts (>4 cm) may cause more complications due to location and size, warranting excision 3
- Clinical evaluation may be difficult with significant axillary scarring—ultrasound evaluation is particularly helpful in these cases 1