CNS & pituitary tumors
Cysts
Colloid cyst
Author: Eman Abdelzaher, M.D., Ph.D.
Last author update: 1 February 2012
Last staff update: 29 July 2020
Copyright: 2002-2023, PathologyOutlines.com, Inc.
PubMed Search: Colloid cyst [title] CNS cyst
Table of Contents
Definition / general | Sites | Clinical features | Radiology description | Radiology images | Case reports | Gross description | Gross images | Microscopic (histologic) description | Positive stainsCite this page: Abdelzaher E. Colloid cyst. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/cnstumorcolloidcyst.html. Accessed April 2nd, 2023.
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
Case reports
- 36 year old woman with AIDS, headache, nuchal rigidity (AJNR Am J Neuroradiology 2000;21:1470)
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
