CNS tumor
CNS cysts
Colloid cyst

Author: Eman Abdelzaher, M.D., Ph.D. (see Authors page)

Revised: 22 August 2017, last major update February 2012

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

PubMed Search: Colloid cyst [title] CNS cyst

Cite this page: Abdelzaher, E. Colloid cyst. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/cnstumorcolloidcyst.html. Accessed October 20th, 2017.
Definition / general
  • Benign unilocular, epithelium lined, mucin filled cyst of third ventricle (eMedicine: Colloid Cysts)
  • Uncertain histogenesis, mostly of endodermal derivation
  • Usually adults (20 - 50 years), rare in children
  • Site, radiologic and pathologic features are distinctive so differential diagnosis may be limited
Sites
  • Anterior third ventricle near foramen of Monro
Clinical features
  • Due to its position, causes intermittent obstruction of CSF flow and headache is most common symptom
  • Sudden impaction causes transient lower limb paralysis (drop attacks) and may be fatal
  • May rupture and mimic abscess or ventriculitis unless colloid is identified
Radiology description
  • Spherical nonenhancing discrete lesion at anterior third ventricle
Radiology images

Images hosted on other servers:

Various images

MR: colloid cyst

Case reports
Gross description
  • 1 cm or larger
  • Round, unilocular with thin glistening wall
  • Cyst filled with turbid and viscid material that solidifies after fixation
Gross images

Images hosted on other servers:

Obstruction of foramen of Monro by gelatinous cyst

Microscopic (histologic) description
  • Hypocellular fibrous wall lined by simple columnar epithelium with variable cilia or mucin (resembles bronchial epithelium); may be pseudostratified or flattened
  • Unlike Rathke cleft and enterogenous cysts, lining epithelium is not prone to squamous metaplasia
  • Fragments of normal choroid plexus are frequently attached to cyst
  • Cyst content may show ghosts of desquamated lining cells, eosinophilic filamentous material resembling actinomyces
  • In chronic lesions, a xanthogranulomatous reaction may occur
Microscopic (histologic) images

Images hosted on other servers:

Ciliated cuboidal cells

Epithelium

Cyst wall

High power

Positive stains