|
A 43 year-old woman presented for evaluation of long-standing complex partial seizures. |
| Arachnoid Cyst of the Middle Cranial Fossa:
(Left)
T1-weighted axial MRI; (Right) T2-weighted axial MRI. Note
the small cyst in the right middle cranial fossa, anterior to the temporal lobe.
The cyst contains fluid, thus it is dark on T1- and bright on
T2-weighted images. Arachnoid cysts are common congenital malformations. They contain fluid but generally do not communicate with the ventricular system. The most common locations are the Sylvian fissure and middle cranial fossa (as in the case above), suprasellar cistern, quadrigeminal cistern, cerebellopontine angle, posterior infratentorial midline, cerebral convexity and interhemispheric fissure. Most are asymptomatic and found incidentally on brain imaging studies. Rarely, they can enlarge and present as a mass lesion with focal neurological signs, seizures or hydrocephalus. |
Revised
11/19/06
Copyrighted 2006. David C Preston