01/11/2025
Subcutaneous cyst at right flank which resectioned under local anesthesia.
🌱🍃
🩺 Subcutaneous cyst
A subcutaneous cyst means a fluid-filled or semi-solid sac located beneath the skin (in the subcutaneous tissue).
It is not “subconscious” — that term refers to the mind, not anatomy.
⸻
⚕️ Common Types of Subcutaneous Cysts
1. Epidermoid cyst (Sebaceous cyst)
• The most common type of subcutaneous cyst.
• Formed when epidermal cells or hair follicle cells get trapped beneath the skin.
• Filled with soft, white keratin (a cheese-like material).
• Common sites: scalp, face, neck, back.
• Usually painless, but can become red, swollen, and painful if infected.
⸻
2. Pilar cyst (Trichilemmal cyst)
• Originates from the outer root sheath of hair follicles.
• Most often found on the scalp.
• Contents are firmer keratin compared to epidermoid cysts.
• Often multiple and may run in families.
⸻
3. Dermoid cyst
• Contains developmental remnants like hair, sebaceous material, or even teeth (in some sites).
• Common in the midline (e.g., near the eyebrow, neck, or coccyx).
• Congenital (present from birth) but may enlarge later.
⸻
🔬 Clinical Features
• Soft or firm lump under the skin.
• Freely movable over deeper structures.
• Non-tender unless inflamed.
• May have a central punctum (tiny opening on top).
⸻
🩹 Treatment
• Definitive: Surgical excision of the entire cyst wall (to prevent recurrence).
• If infected: Incision and drainage first, then excision after infection subsides.