Epidermoid CystEpidermoid Cyst

An epidermoid cyst is a benign, slow-growing lump that forms when keratin-producing cells from the epidermis become trapped beneath the skin. The cells continue producing keratin, the protein also found in hair and nails, and fill a sac beneath the surface. The result is a round, firm, skin-colored or yellowish nodule ranging from a few millimeters to several centimeters across, most often on the face, neck, or trunk. Although commonly called sebaceous cysts, epidermoid cysts contain keratin rather than sebum. They are harmless and may be removed when they become infected, painful, or cosmetically unwelcome. At Wall Street Dermatology, two surgical approaches are used. Conventional excision removes the entire cyst wall and its contents. Minimal excision uses a much smaller opening and leaves a shorter scar. With either approach, the entire capsule must be removed because a retained fragment regenerates the cyst.

4 min read · Last updated: 2026-02-08 · Reviewed by Dr. Julia Tzu , MD, FAAD, FACMS

• Epidermoid cysts form when keratin-producing epidermal cells become trapped beneath the skin [1]
• Complete removal of the cyst including its capsule prevents recurrence [2]
• Without treatment, some cysts may remain small and asymptomatic for years [1]
• Never attempt to drain or pop a cyst yourself as this risks infection [1]

• Round, dome-shaped bump under the skin
• Firm but movable lump
• Skin-colored, whitish, or yellowish color
• Central dark opening (punctum) may be visible
• Usually 1-5 centimeters in diameter
• Generally painless unless infected
• Thick, whitish or yellowish discharge if ruptured
• Redness, warmth, and tenderness when infected

• Signs of infection such as redness, pain, swelling, or warmth
• A cyst that ruptured or drained material with a foul odor
• Rapid growth or a change in how the lump looks or feels
• A location that causes discomfort or gets in the way of normal movement
• Cosmetic concern about the appearance
• Uncertainty about what the growth is
• A cyst on the face or another visible area, where technique choice has a direct bearing on the scar

Have questions about epidermoid cyst? Our team is here to help.

• Implantation of epidermal cells into dermis
• Trauma or injury to skin
• Blocked or damaged hair follicle
• Developmental abnormality
• Acne or skin inflammation
• Surgery scars (implantation cysts)
• Genetic predisposition

We offer a service to help manage this condition: Cosmetic Cyst Removal Surgery .

• Excellent prognosis as these are benign growths
• Complete excision with intact capsule prevents recurrence
• Incomplete removal may lead to recurrence
• Some cysts remain small and stable indefinitely
• Rare malignant transformation (extremely uncommon)
• Infection is treatable with drainage and antibiotics

Triple board-certified cosmetic and surgical dermatologist · Manhattan's Financial District

Trained at Stanford, Johns Hopkins, Penn & NYU

✓ Intact excision of the full capsule to avoid recurrence

Epidermoid cysts tend to come back if the sac ruptures or is left behind, so Dr. Julia Tzu removes the cyst intact along with its full capsule. Her priority is a clean, cosmetically optimized closure that keeps scarring as minimal as possible.

More About Dr. Tzu →

1. What are the symptoms of Epidermoid Cyst?
2. When should you seek care for Epidermoid Cyst?
3. What causes Epidermoid Cyst?
4. How is Epidermoid Cyst treated?
5. Prognosis
6. FAQs
7. Sources

This article draws from 3 peer-reviewed sources.

• [1] Cleveland Clinic – Epidermal Inclusion Cysts (Sebaceous Cysts)
• [2] Cleveland Clinic – Cyst Removal
• [3] Mayo Clinic – Epidermoid Cysts

Medically reviewed by Dr. Julia Tzu , MD, FAAD, FACMS · Last reviewed: 2026-08-31