From the case:
Perineural cyst around S1 nerve root
Loading images...
Axial T1
Surrounding the right S1 nerve root is a CSF intensity space with associated bony remodeling.
Typical features of a Tarlov cyst.
Case Discussion
A Tarlov cyst (also called a perineural cyst) is a CSF filled dilatation of the nerve root sheath at the dorsal root ganglion. These are type II spinal meningeal cysts that are, by definition, extra dural, but contain neural tissue.