An epidermoid tumor (also known as a germ cell or pearly tumor) is a benign, slow-growing tumor that arises from the inappropriate formation of ectodermal tissue during fetal development.  The tumors are rare, accounting for less than two percent of all brain tumors, and often are not diagnosed until adulthood because they grow very slowly. Epidermoid tumors usually occur on the skull, spine or brain.  


Epidermoid tumors are considered congenital, occurring around the third to fifth week of fetal development.  On very rare occasions, they can be acquired through trauma.  


There are no known risk factors associated with an increased chance of developing epidermoid tumors.


Symptoms will vary based on the location of the tumor and its effect on the surrounding tissue.  They may include:

  • Headache
  • Fever
  • Neck stiffness
  • Facial pain
  • Weakness
  • Imbalance
  • Loss of vision
  • Loss of hearing
  • Seizure
  • Meningitis (in rare cases where the tumor ruptures)


Epidermoid tumors are diagnosed through MRI or CT scans.


Epidermoid tumors are treated with surgical removal, assisted by endoscopy if possible.  Total removal is curative.  If some of the tumor is left behind because of adhesion to the nerves or brain stem, it may grow back.


There is no known way to prevent epidermoid tumors.


Content generated and provided by Joshua B. Bederson, MD, Professor and Chairman of the Department of Neurosurgery at The Mount Sinai Health System.  Some of the information contained in this article was adapted from the National Institutes of Health.  Last reviewed June 2011 by the Department of Neurosurgery at The Mount Sinai Health System.

If you want to learn more about treating epidermoid tumors call the Mount Sinai Department of Neurosurgery at 212-241-2377.