Dermoids

Etiology

  1. benign cystic lesions that are choristomas (tumors composed of tissues not usually found at the involved site)
  2. originate at bony suture sites during embryogenesis as a lead to of surface skin elements becoming entrapped
  3. usually found in early childhood (25% are noted at birth), but can also be diagnosed in adults
    • in adults, they often involve the deep orbital tissues and grow to a very large size
  4. Not to be confused with Epidermoid cysts which are   similar but lack certain elements in the wall of the cyst

Differential Diagnosis

  • encephalocele
  • lacrimal mass/tumor
  • lacrimal mass or tumor

Work-up / Course / Prognosis

CT/MRI imaging reveals characteristic round to oval shaped cystic lesion with a defined lining

Symptoms

  • painless
  • slow-growing

Signs

  • typically do not displace the globe
  • typically do not raise intraocular pressure

Locations

  • occur in the superotemporal  orbit (the most common site, 70% )
  • the superomedial orbit
  • deep orbit

Trauma might lead to leakage of the cystic contents and likely will lead to in acute inflammation

Pathology

Lining

  • the cysts are lined by keratinizing, stratified squamous epithelium (85% of lesions), or
  • nonkeratinized stratified squamous epithelium

Filling

  • filled with keratin
  • hair shafts are usually present in lumen or wall of cyst (99%)
  • sebaceous glands are usually present in lumen or wall of cyst (75%)
  • sweat glands are often present in lumen or wall of cyst (20%)

Treatment

  • surgical excision is the treatment of choice. With complete excision, the prognosis is excellent.
  • usually once they child has reached age 12 months

BEFORE & AFTER

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