Sebaceous (Epidermoid) Cyst

General Surgery

Benign cyst lined by epidermis containing keratin debris; common on scalp, face, neck, scrotum.

History taking

  • Slow-growing, painless swelling; occasionally discharges cheesy material
  • Episodes of infection — pain, redness, discharge

Examination

  • Spherical, smooth, firm, tethered to skin with central punctum
  • Inflamed/abscessed if infected

Red flags

  • Rapid growth, ulceration, bleeding — exclude malignancy

Differential diagnosis

  • Lipoma, dermoid cyst, neurofibroma, lymph node

Recommended investigations

  • Clinical diagnosis

Diagnosis

  • Clinical

Initial treatment / management

  • Asymptomatic: observation
  • Symptomatic/recurrent infection: complete excision under LA when not inflamed
  • Infected: incision & drainage, antibiotics, plan excision later

Prescription examples

  • Tab Cefalexin 500 mg PO QID x 5 d for infected cyst with cellulitis
  • Post-op simple analgesia

Follow-up advice

  • Wound review 7 days; ensure complete capsule removal to prevent recurrence

Patient counselling

  • Recurrence if capsule incompletely removed

Referral criteria

  • Recurrent or large cysts for definitive surgery

Clinical pearls

  • Central punctum is the diagnostic clue
  • Do not excise during active infection — drain first, excise later

References

  • Bailey & Love's Short Practice of Surgery 28e

Educational outpatient guide — verify against local guidelines before clinical use.

WardRound

WardRound

Clinical Decisions in Seconds