Vacuum epidural cyst with acute neurological presentation. A case report

Abstract

The widespread use of MRI in the assessment of low back pain has led to increased detection of degenerative cysts of the spine, which was essentially a surgical diagnosis earlier. The awareness of degenerative cysts, the significance of their role in the etiology of radicular and back pain and their effective management is evolving. We describe a case of bilateral, gas-filled lumbar facet synovial/ ganglion cysts causing focal arachnoid inflammation and lateral lumbar canal stenosis.

Figure 1

A) Axial T2-weighted MRI of the lumbosacral (LS) spine at L4-L5 level demonstrates a hypointense lesion in right lateral epidural space (long arrow) causing mass effect on the thecal sac and a smaller cyst (short arrow) in left epidural space. B) Sagittal T2-weighted image of the LS spine demonstrates crowding of the cauda equina spinal nerve roots (short arrow) by the epidural lesion. C) Axial post-contrast fat-saturated T1-weighted MRI showing enhancement of the wall of the right epidural gas cyst and adjacent thickened thecal sac (arrows).

Figure 2

A, B) Axial CT scan at L4-L5 level (soft tissue window), showing a larger right epidural vacuum (gas) cyst (long arrows in A, B), a smaller left epidural vacuum (gas) cyst (short arrow in B) and bilateral facet joint arthropathy with joint vacuum phenomenon (short arrows in A).