Sebaceous cyst – Causes, Symptoms, Diagnosis, Treatment and Ongoing care

Basics

Synonyms: Epidermoid cysts, epidermal cysts, epidermal inclusion cysts, keratin cyst

Description

A benign encapsulated subepidermal lesion that is filled with keratin

Epidemiology

• Most common cutaneous cyst
• Male:Female Ratio is 2:1
• Most common in 3rd to 4th decade of life

Risk Factors

Genetics

• Gardner syndrome (autosomal dominant)
• Gorlin syndrome (autosomal dominant)
• Pachyonychia congenita type II (autosomal dominant)

Pathophysiology

Pilosebaceous follicles that are either obstructed or ruptured resulting in the accumulation of keratin in the subepidermis or dermis layer of the skin.

Etiology

• Spontaneous
• Trauma
• Congenital

Diagnosis

History

• Mass slowly growing over time
• Recent trauma
• “Cheese-like” material from cyst

Physical Exam

• Firm to fluctuant, mobile, dome-shaped, flesh-to-yellow colored.
• Commonly located on face, neck, upper back, and chest; ff due to trauma, on buttocks, palms, or plantar side of feet.
• Varying in size (few millimeters to centimeters)
• Cyst with or without comedo
• Signs of rupture or inflammation (erthyema, tenderness, swelling)

Diagnostic Tests & Interpretation

Diagnosis is by clinical examination

Diagnostic Procedures/Surgery

Histological examination of excised mass is debatable (1)[C].

Pathological Findings

• Stratified, squamous lining
• Granular layer
• Eosinophilic keratinacous debris

Differential Diagnosis

• Trichilemmal cyst (Pilar cyst)
• Lipoma
• Steatocystoma

Treatment

Sebaceous cysts are generally benign and do not require excision.

Surgery/Other Procedures

• Indications
  • Cosmetic reasons
  • Inflamed cyst (must wait till inflammation subsides) (2)[C]
  • Cyst impairing patient’s functioning
• For 1–2-cm uncomplicated cysts, a punch biopsy is superior to a elliptical incision to allow for its expulsion by lateral pressure (3)[B].
• No published data on effectiveness of minimal excision technique
• Must ensure that entire cyst wall has been removed to prevent reoccurrence.

Ongoing Care

Follow-Up Recommendations

• Uncomplicated sebaceous cysts do not require follow-up.
• Any reoccurrence of cysts should be excised using an elliptical incision.
• Solid or atypical masses noted in excision should be followed up with histological analysis.

Prognosis

Overall reoccurrence rate after excision is <3% (less with elliptical incision versus punch biopsy).

Complications

• Rupture of sebaceous cyst resulting in foreign-body giant cell reaction.
• Secondary polymicrobial infection
• Rare: Transition into malignancy (squamous cell carcinoma, basal cell carcinoma)

References

1. Zuber TJ et al. Minimal excision technique for epidermoid (sebaceous) cysts. Am Fam Physician. 2002;65:

2. Moore RB, Fagan EB, Hulkower S, Skolnik DC, O’Sullivan G et al. Clinical inquiries. What’s the best treatment for sebaceous cysts? J Fam Pract. 2007;56:315–6.

3. Lee HE, Yang CH, Chen CH, Hong HS, Kuan YZ et al. Comparison of the surgical outcomes of punch incision and elliptical excision in treating epidermal inclusion cysts: a prospective, randomized study. Dermatol Surg. 2006;32:520–5.

Clinical Pearls

• Sebaceous cysts are generally benign and do not require excision.
• For 1–2-cm uncomplicated cysts, a punch biopsy is superior to a elliptical incision to allow for its expulsion by lateral pressure (3)[B].
• Must ensure that entire cyst wall have been removed to prevent reoccurrence.
• Solid or atypical masses noted in excision should be followed up with histological analysis

Codes

ICD9

706.2 Sebaceous cyst

Snomed

419603000 epidermoid cyst of skin (disorder)