What is the recommended management of a non‑inflamed sebaceous (epidermoid) cyst in an otherwise healthy adult?

Management of Non-Inflamed Sebaceous (Epidermoid) Cysts

For a non-inflamed epidermoid cyst in a healthy adult, observation without intervention is appropriate, as these cysts contain normal skin flora even when uninflamed and do not require treatment unless they become symptomatic or inflamed. 1

Understanding the Nature of Non-Inflamed Cysts

• Epidermoid cysts (often mislabeled "sebaceous cysts") ordinarily contain skin flora in the cheesy keratinous material even when uninflamed 1
• The inflammation and purulence that sometimes occur result from rupture of the cyst wall and extrusion of contents into the dermis, rather than from infectious complications 1
• These are benign epithelial lesions that typically present as firm, skin-colored nodules filled with keratinous material 2

When to Intervene vs. Observe

Indications for surgical excision include:

• Inflamed or infected cysts - these require incision, thorough evacuation of pus, and probing the cavity to break up loculations 1
• Progressive growth over 3 months - indicates active pathology requiring medical intervention 3
• Multiple cysts in cosmetically or functionally sensitive areas (particularly the face) - warrant complete surgical excision 3
• High clinical suspicion for malignancy - though rare, malignant transformation to squamous cell carcinoma can occur and requires excision with histopathological evaluation 2

For asymptomatic, non-inflamed cysts:

• Observation is reasonable as patients are typically asymptomatic 2
• No urgent intervention is needed unless the patient desires removal for cosmetic reasons or the cyst becomes symptomatic 4

Surgical Approach When Treatment is Indicated

For inflamed cysts:

• Incision and drainage is the recommended treatment 5
• Simply cover the surgical site with a dry dressing - this is usually the easiest and most effective wound treatment 1
• Packing with gauze causes more pain without improving healing 5
• Gram stain, culture, and systemic antibiotics are rarely necessary 1, 5

Antibiotics are only indicated when:

• Multiple lesions are present 1
• Extensive surrounding cellulitis exists 1
• Systemic inflammatory response syndrome (SIRS) is present: temperature >38°C or <36°C, tachypnea >24 breaths/minute, tachycardia >90 beats/minute, or WBC >12,000 or <4,000 cells/µL 5
• Severely impaired host defenses 1
• An antibiotic active against MRSA is recommended for patients with markedly impaired host defenses or SIRS 5

For elective excision of non-inflamed cysts:

• Wide local excision with complete removal of the entire cyst wall is necessary to prevent recurrence 3
• Minimal excision techniques through the keratin-filled orifice can achieve excellent cosmetic outcomes, particularly for facial cysts (mean wound length 0.93 cm, mean operative time 15.2 minutes) 4
• Alternative two-step approach: laser punch to remove content, followed by minimal excision of cyst wall approximately 1 month later 6
• All surgically excised cysts should undergo histopathological evaluation to rule out malignancy and confirm clear margins 3, 2

Critical Pitfalls to Avoid

• Do not routinely culture or prescribe antibiotics for simple inflamed epidermoid cysts without systemic signs of infection 5
• Do not use ultrasonographically guided needle aspiration - it has only 25% success rate overall and <10% success with MRSA infections 5
• Do not treat multiple infected facial cysts as merely cosmetic - this can lead to progression of infection and worse outcomes 3
• Do not perform incomplete excision - failure to remove the entire cyst wall leads to recurrence 3
• Maintain vigilance for rare malignant transformation, particularly in long-standing cysts, and have a low threshold for histological examination 2, 7