Two cases of ganglion cysts in the lumbar spinal canal: MR findings. Ganglion cysts in the spinal canal are rare. To our knowledge, only 12 cases have been reported. In addition, ganglion cysts depicted by MR are extremely rare. We report the MR findings in two cases of ganglion cysts in the lumbar spinal canal. In both cases, the ganglion cysts were slightly higher in intensity than CSF on T2-weighted images. In addition, a thin band of low intensity was depicted around the ganglion in both cases. This finding may help to diagnose ganglion in the spinal canal. On T1-weighted images, the signal intensity of the ganglion was very similar to that of the intervertebral disc in both cases. In summary, although ganglion mimics disc hernia or sequestrated disc on both T2- and T1-weighted images, the possibility of a ganglion should be considered whenever an extradural mass showing high signal intensity surrounded by a thin band of low intensity is identified on T2-weighted images.