CNS & pituitary tumors


Dermoid cyst

Last author update: 1 February 2012
Last staff update: 29 July 2020

Copyright: 2002-2024,, Inc.

PubMed Search: Dermoid cyst [title] central nervous system

Eman Abdelzaher, M.D., Ph.D.
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Cite this page: Abdelzaher E. Dermoid cyst. website. Accessed April 14th, 2024.
Definition / general
  • Developmental lesions arising from embryologic displacement of ectoderm into meninges, ventricles or rarely parenchyma (eMedicine: Imaging in CNS Dermoid Tumors)
  • Benign cyst lined by keratinizing squamous epithelium and cutaneous adnexa
  • Uncommon; much less common than epidermoid cyst
  • Usually affects children
  • Distribution more restricted than epidermoid cysts, usually affects midline (mostly fontanelle or posterior fossa as midline cerebellar lesions or within the 4th ventricle), may affect spinal canal
  • May have sinus tract to skin surface in nasofrontal or occipital regions
  • May rupture and cause chemical meningitis
Gross description
  • Thick walled with greasy pilosebaceous contents
Microscopic (histologic) description
  • Fibrous wall lined by keratinizing squamous epithelium with skin adnexa, cyst contains squames, hair, sebum
  • Hair shafts highlighted with polarized light
  • May be hair matrix differentiation (shadow cells)
  • Rupture may cause granulomatous inflammation with foreign body giant cell reaction
Positive stains
Differential diagnosis
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