Ironclad here!! I need feedback on what this thing is really? I'm curious, because my granma ma has this and I need insight! Anyone got advice on this?

Arachnoid cysts are cerebrospinal fluid covered by arachnoidal cells and collagen[1] that may develop between the surface of the brain and the cranial base or on the arachnoid membrane, one of the three membranes that cover the brain and the spinal cord.[2] Arachnoid cysts are a congenital disorder,[3] and most cases begin during infancy; however, onset may be delayed until adolescence.[2]

Prognosis--Untreated, arachnoid cysts may cause permanent severe neurological damage due to the progressive expansion of the cyst(s) or hemorrhage (bleeding).[2] However, with treatment most individuals with arachnoid cysts do well.

More specific prognoses are listed below:

Patients with impaired preoperative cognition had postoperative improvement after surgical decompression of the cyst.[27][28]
Surgery can resolve psychiatric manifestations in selected cases.

Info from : Arachnoid cyst - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Arachnoid_cysts#Prognosis)

Arachnoid cysts are cerebrospinal fluid covered by arachnoidal cells and collagen[1] that may develop between the surface of the brain and the cranial base or on the arachnoid membrane, one of the three membranes that cover the brain and the spinal cord.[2] Arachnoid cysts are a congenital disorder,[3] and most cases begin during infancy; however, onset may be delayed until adolescence.[2]

Prognosis--Untreated, arachnoid cysts may cause permanent severe neurological damage due to the progressive expansion of the cyst(s) or hemorrhage (bleeding).[2] However, with treatment most individuals with arachnoid cysts do well.

More specific prognoses are listed below:

Patients with impaired preoperative cognition had postoperative improvement after surgical decompression of the cyst.[27][28]
Surgery can resolve psychiatric manifestations in selected cases.

Info from : Arachnoid cyst - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Arachnoid_cysts#Prognosis)

Hay thanks man!! I'm nervous for my grandmas health you know! Now that I have a good idea on what it is, I'm relevied a little, thanks for the feedback!