Brain Tumor, Epidermoid



  • Epidermoid tumors are benign, congenital cysts that occur intradurally and extradurally. They are slow-growing and produce symptoms gradually.
  • Also called epidermoid cysts, primary cholesteatomas, and epidermoid inclusion cysts
  • Third most common tumors of the cerebellopontine angle (CPA)


Rare intracranial growths constituting 1.8–2.2% of all intracranial tumors

  • Presentation can be at any age but most commonly between the 3rd and 5th decades of life.
  • Equal incidence in men and women
  • There is a wide ethnic distribution, and there is no known preponderance in any region.

Etiology and Pathophysiology

  • Considered a benign lesion; malignant transformation is rare.
  • Growth is secondary to accumulation of desquamated epithelial cells; follows a linear growth rate
  • Symptoms are due to mass effect and displacement of local structures. Depending on tumor location, it may result in cranial nerve, blood vessel, and brainstem compression.
  • Derived from squamous epithelium that is included during neural tube closure
  • Epidermoid tumors grow slowly from the buildup of keratin and cholesterol from the continual shedding of the epithelium lining the cyst.
  • Formed at the time of neural tube closure between the 3rd and 5th weeks of embryonic life
  • Common locations include CPA, parapontine, parapituitary, middle cranial fossa, and dipole of the fontanel.
  • Multiple lumbar punctures have been known to be a rare cause.

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