Sebaceous cyst

Sebaceous cysts, also known as epidermoid cysts or keratin cysts, are common noncancerous cysts that occur under the skin. They typically arise from hair follicles or skin glands.

Causes:

  • Blocked Sebaceous Glands: When these oil-producing glands get blocked, cysts may form.
  • Trauma: Damage to the skin or hair follicle can lead to cyst formation.
  • Developmental Anomalies: During skin development, cells can become trapped.
  • Genetic Conditions: Such as Gardner’s syndrome or basal cell nevus syndrome.

Diagnosis:

  • Clinical Examination: Typically presents as a round, firm lump under the skin, often with a central punctum (a small blackhead-like opening). They’re usually painless unless infected.
  • Ultrasound: Can be used to determine the content and depth of the cyst.
  • Fine-Needle Aspiration: Rarely needed, to examine the cystic fluid and rule out other conditions.
  • Biopsy: Rarely needed, but can be done to exclude malignancy.

Differential Diagnosis:

  • Lipoma: A soft, movable lump under the skin, made up of fat cells.
  • Ganglion Cyst: A fluid-filled lump near joints or tendons.
  • Pilar Cyst: Similar to sebaceous cysts, but typically occur on the scalp.
  • Abscess: A painful, pus-filled lump caused by infection.
  • Cancerous Tumors: Though rare, it’s important to rule out skin cancers.

Management:

  • Observation: If the cyst is small and asymptomatic, no immediate treatment may be needed.
  • Warm Compresses: Can help the cyst drain on its own.
  • Incision and Drainage: For symptomatic relief, especially if the cyst is inflamed or infected, but recurrence is common with this method.
  • Excision: Surgical removal of the entire cyst is the most definitive treatment to prevent recurrence. This is usually done under local anesthesia.
  • Antibiotics: If there’s evidence of bacterial infection.
  • When to Seek Medical Care:
    • If the cyst becomes painful, red, or swollen
    • If there’s a rapid increase in size or changes in appearance.
    • If the cyst is in a location that causes cosmetic concerns or functional impairment.
  • Follow-Up:
    • Regular monitoring of the cyst for any changes.
    • If surgically removed, a follow-up appointment is needed to ensure proper healing and to remove sutures if necessary.