Findings:
Voluminous perineural cyst occupying the spinal canal from L4 to S3-S4 with diameters of 12 x 6.5 cm, with completely liquid content. Significant bony remodeling of the posterior aspect of the L4 and L5 vertebrae as well as the sacrum secondary to mass effect with widening of the left-sided neural foramina at L4/5 and L5/S1.
Consequential displacement of the dural sac to the right without any central canal stenosis or nerve root impingement.
No bone marrow oedema. No disc herniation or relevant stenosis.
Conclusion:
Large Tarlov cyst in the lower lumbar spine, as described above.