• Sebaceous (or epidermoid) cyst is a common benign lesion presenting as a solid, raised subepidermal nodule filled with a mixture of lipids called sebum.
  • Classically present as skin-coloured dermal nodules, often with a clinically visible central punctum (Figure 1 and 2).
    • Cosmetic concern; infected and occasionally painful.
  • Lesions can present anywhere but primarily present on the scalp, face, neck upper back and upper chest.
  • Size ranges from a few millimeters to several centimeters in diameter.
• Pathophysiology
  • Plugging of the follicular orifice of the sebaceous gland (oil producing gland).
  • Common in those with acne vulgaris.
• Due to the inflammatory reaction from the release of lipid contents, practitioners will mistake sebaceous for an abscess and prescribe antibiotics.

Evaluation

• Clinical diagnosis based on clinical appearance of a discrete cyst or nodule, often with a central punctum, that is freely movable on palpation.
• Diagnosis is confirmed by histologic examination but is rarely needed.

• Inflamed, uninfected sebaceous cysts may resolve spontaneously without therapy. Treatment is not necessary unless desired by the patient.
• Excision should be delayed if an active infection is present. In this case, an initial incision and drainage may be indicated with potential for recurrence in the future.
• If the cyst has ruptured and the cyst wall lining is destroyed, the cyst often will not reoccur.

Injection

• For inflamed, non-fluctuant lesions and complications of cyst rupture such as erythema, swelling and pain.
• Injection of intralesional triamicinolone acetonide (3 mg/mL for the face and 10 mg/mL for the trunk) into the inflamed lesion improves resolution of inflammation and may prevent infection and the need for incision and drainage.
• For fluctuant lesions, excision or incision techniques may be used as described below.

Excision

• Excision is best accomplished when the lesion is not inflamed as inflammation increases recurrence as tissue planes less distinct.
• Minimal excision technique is used to rupture the cyst and drain its contents. The cyst wall is removed through the incision.

Incision and Drainage

• For noninflamed, non-ruptured and noninfected cysts.
• Punch incision technique (4 mm punch) or minimal incision technique (no. 11 blade) can be used to remove uncomplicated cysts. The cyst content is then drained by exerting a vigorous lateral pressure on the cyst.
• Anesthesia with 1% lidocaine should be injected around the lesion to avoid rupturing the cyst wall with the pressure of the anesthetic agent.
• The minimal incision technique provides better cosmetic results than the standard excision and is useful for cysts in cosmetically sensitive areas.

• Most sebaceous cysts can be managed as an outpatient.

• Most sebaceous cysts do not require transfer to another facility.

• Consultations are not necessary unless the cyst is large and in a cosmetically important location such as the mouth or face. In this case, refer to a dermatologist/plastic surgeon.
• Adults with epidermoid cysts in rare locations such as the fingers and toes, history of multiple lipomas, and a family history of colon cancer should raise the suspicion of Gardner syndrome with an appropriate specialist referral.
• Rare malignancy can arise. Squamous cell carcinoma is the most common malignancy followed by basal cell carcinoma. A consultation may be warranted.

• Following surgical excision, contact sports and strenuous activity should be avoided.
• Sutures may be removed within 7-10 days.
• Patients should be instructed that the surgical scar will generally take 8 weeks to reach a maximum of 80% tensile strength of the original skin strength.
• Scar revision, if necessary, should take place between 6 months to 1 year following excision as the remodeling phase of wound healing occurs between 3 weeks to 1 year.

1. Goldstein, BG., Goldstein, O. Overview of benign lesions of the skin – UpToDate [Internet]. [cited 2021, Feb 1]

   
   

2. Zito, P. M., & Scharf, R. (2019). Cyst, Epidermoid (Sebaceous Cyst). StatPearls [PubMed – ncbi.nlm.nih.gov]

   
   

3. Sempowski, I. P. (2006). Sebaceous cysts: Ten tips for easier excision. Canadian family physician, 52(3), 315.