What is the treatment for an epidermoid cyst on the back?

Treatment of Epidermoid Cyst on the Back

Complete surgical excision with removal of the entire cyst wall is the recommended treatment for non-inflamed epidermoid cysts on the back to prevent recurrence. 1

Diagnosis and Assessment

• Epidermoid cysts (also called sebaceous cysts) are benign, encapsulated subepidermal nodules filled with keratin material
• They appear as dome-shaped lesions that elevate the skin and often have a central punctum (opening)
• On the back, these cysts are common due to the abundance of hair follicles in this area
• Ultrasound can confirm diagnosis showing a well-circumscribed, avascular mass with acoustic amplification 2

Treatment Algorithm

For Non-Inflamed Epidermoid Cysts:

1. Complete surgical excision is the treatment of choice

   • Requires removal of the entire cyst wall with a minimum 4-mm margin around the cyst border 1
   • Technique involves making an elliptical incision over the cyst, carefully dissecting around the cyst wall, and removing the entire cyst intact 1

2. Minimal excision technique is a less invasive alternative

   • Involves making a 2-3 mm incision, expressing cyst contents through compression, and extracting the cyst wall through the small incision
   • Does not require suture closure
   • Easier to perform and learn (most physicians can perform after 3-5 precepted sessions) 3

For Inflamed/Infected Epidermoid Cysts:

1. Incision and drainage is the definitive treatment 1
2. Antibiotics should be reserved only for:
   • Signs of systemic inflammatory response syndrome (SIRS)
   • Patients with markedly impaired host defenses
   • Extensive surrounding cellulitis
   • Failed initial treatment 1
3. Postpone complete excision until inflammation has subsided, as inflamed cysts are difficult to excise 3

Post-Procedure Care

• Cover the surgical site with a dry dressing
• Keep the wound clean and dry
• Monitor for signs of infection
• Schedule follow-up to assess wound healing and remove sutures (typically within 7-14 days) 1

Important Considerations

• Recurrence rates range from 2.2-8.3% depending on the technique used, with the main cause being incomplete removal of the cyst wall 1, 4
• Histopathological examination is recommended if:
  • Cyst size is >1.5 cm
  • Suspicious features are present (nodular mass, ulceration, rapid growth, fixation to surrounding tissues)
  • Unusual clinical presentation 1
• Infection is the most common complication, occurring as a reaction to rupture of the cyst wall 1

Antibiotic Options (if needed for infection)

First-line oral options include:

• Dicloxacillin
• Cephalexin
• Clindamycin

Treatment duration:

• 7-10 days for uncomplicated infections
• Up to 14 days for more severe infections 1

Pitfalls to Avoid

1. Incomplete excision: Failure to remove the entire cyst wall is the primary cause of recurrence
2. Unnecessary antibiotics: Not routinely needed for simple incision and drainage without systemic symptoms
3. Operating on inflamed cysts: Better to wait until inflammation subsides before attempting complete excision
4. Missing malignant transformation: Though rare, submit suspicious lesions for pathological examination 1, 5