5/3/2009 Case 1 Answer

Fans of Rob's Radiology - this is a Colloid Cyst.

1. Benign lesion in the anterior 3rd ventricle (near foramen of Monro)
2. Neuroepithelial in origin - is the leading theory
3. Can cause sudden death by obstructing the foramen of Monro
4. May have pendulous attachment to 3rd ventricular roof
5. Usually found in adults but has been reported in children
6. Often found incidentally
7. Headaches - brief and intermittent
8. Headaches - in some patients are positional
9. Hydrocephalus, drop attacks, momentary loss of consciousness, progressive dementia, papilledema, diplopia,
10. CT - typically dense and near the foramen of Monro
11. MRI - variable appearance depending on the contents - most common Bright on T1 and dark on T2
12. Can be followed but commonly surgically resected to prevent the risk of sudden death.

references - http://www.ajnr.org/cgi/content/full/21/8/1470 and emedicine.com