Re: subarachnoid cyst

Posted By CCF Neurology W6 MD on December 10, 1998 at 21:21:44:

In Reply to: subarachnoid cyst posted by Atie on December 09, 1998 at 16:17:24:






My brother is 33 years old and suffers from mild-moderate headaches.
He recently had a CT Scan done.  The report said:  
The paranasal sinuses and mastoids in general are clear.  The ventricular
and cisternal spaces are normal in size and configuration.  There is no mass
legion, or midline shift evident.  Intracranially there is an expaned fluid
space probably related to subarachnoid cyst along the medial margin of the
middle cranial fossa on the left.  This measures approx 2 by 1 cm in
dimension.  Overall, no significant abnormality for age.
The doctor suggested that given that medicines were effective in
curing the migraine headaches, the probable subarachnoid cyst was nothing to worry
about.  (There is a long history of Migraine in our family.)
Is that indeed correct?  Can these cysts grow in size and become a problem
in future?  How common is this ailment and how often should future CT Scans
be done to keep track of the cyst's growth?
Thank you,
Atie
  =


Dear Atie,
Arachnoid cysts are congenital fluid collection located most commonly in the middle cranial fossa (as is the case in your brother). It  represents about one percent of all masses in the cranium. Between 60-80% of all arachnoid cysts may cause symptoms, ranging from headaches, seizures, and focal neurologic signs. The natural history of these cyst is unclear. Most cysts remain unchanged in size with advancing age, there is a  subgroup of larger cysts that may ex pand with time. Unless there is new symptoms or a change in the frequency or quality of the headache, repeat CT is NOT necessary. Good luck and I hope the above information helps.