Posterior thecal lumbar disc herniation mimicking synovial cyst

Abstract

We describe a 70 year-old-patient with a rare, misleading presentation of lumbar disc prolapse, which on CT mimicked a synovial cyst. The whole nucleus pulposus had herniated, become sequestrated, and migrated behind the theca adjacent to the L4-5 facet joint. There was no continuity of the disc material with the intervertebral space. A fenestration was performed and the sequestrated disc material was found free of adhesions, and removed completely without difficulty. Histopathological examination confirmed the diagnosis. The patient had complete relief from his pain.

Endoscopic removal of herniated nucleus pulposus migrated dorsally to the dural sac

“…Because of the rather low prevalence of the posteriorly migrated HNP, differential diagnosis is extremely important. For the differential diagnosis, Sakas et al introduced a case that mimicked a synovial cyst of the facet joint, as the HNP was displaced in the vicinity of the facet joint (6). Their report appeared to be comparable to our case, because the MRIs of the current case showed a capsularized mass.…”

“…A migrated HNP, called the sequestrated type, is not a rare condition. However, it is rare for the direction of migration to be toward the dorsal aspect of the dural sac, as it is usually cranial or caudal at the ventral aspect of the dural sac (1)(2)(3)(4)(5)(6)(7). The clinical difficulty with the dorsally migrated HNP lies in the diagnosis; it is very hard to distinguish from an epidural tumor with an MRI because of the similarity in location and shape (2,6).…”

Retrospective report of symptomatic postoperative discal pseudocyst after lumbar discectomy

“…Also, the cyst wall is lined by a few fibrinoid materials (arrowhead) without any epithelial cells. (Hematoxylin and eosin, ×100) cysts arising from the facet joint, posterior longitudinal ligament, ligamentum flavum, perineurium, arachnoid, and disc [24][25][26][27][28][29][30]. Among these epidural cysts, discal cysts share an origin and many other features with PDP.…”

Posterior Epidural Migration of Lumbar Disc Fragments

“…These fragments are known to migrate superiorly, inferiorly, or laterally, 1 but posterior epidural migration is exceptionally rare. 1,2,4,5,6,19,20,23 Patients with disc fragments generally present with radiculopathy, but may also present with cauda equina syndrome. 23, 24 We report three cases of sequestered disc fragments posterior to the thecal sac; two cases presented with cauda equina syndrome and one with radiculopathy.…”