The spinal manifestations of spontaneous intracranial hypotension are infrequently described and most often encountered when a spinal MRI is performed to search for a site of CSF leak.

Typically, MRI reveals an extensive nonfocal extradural CSF collection (spinal hygroma) that is isointense to CSF and contains dilated epidural veins. The dural sac usually maintains its midline attachment to the posterior longitudinal ligament with the collapse of the anterolateral thecal sac, giving a 'festooned' appearance. Smooth circumferential dural enhancement is common. Occasionally, delayed contrast leak into the collections has been described (as in this case).

Importantly, it is common to see a 'collection' of CSF between the spinous processes of C1 and C2. This is the C1-C2 false localizing sign and should not be mistaken for the site of the CSF leak.