colloid cyst
Pronunciation: KOL-oid sist
Benign cystic lesion typically located in the third ventricle that can cause intermittent hydrocephalus.
Full Definition
A colloid cyst is a benign, epithelium-lined cystic lesion that most commonly occurs in the anterior third ventricle, particularly near the foramen of Monro. These cysts contain viscous, proteinaceous material that gives them characteristic imaging appearances. On CT, colloid cysts typically appear as well-circumscribed, hyperdense lesions, while on MRI they show variable signal depending on their protein content and hydration state. Although benign, colloid cysts can cause intermittent obstruction of cerebrospinal fluid flow, leading to acute hydrocephalus and potentially life-threatening symptoms including sudden death.
Usage
Usage note: Specify location and relationship to cerebrospinal fluid pathways.
In Context
- "A small colloid cyst is incidentally noted at the foramen of Monro without ventricular dilatation." — Routine MRI report
- "The patient's acute hydrocephalus was caused by a colloid cyst obstructing the foramen of Monro." — Emergency neurosurgical consultation