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Neuroradiology Case of the Week

Case 448

October 2009

Sharayne Mark and P-L Westesson, MD, PhD, DDS

Clinical Presentation: A 55-year-old male with history of right leg weakness presented for a follow-up MRI study.

Imaging Findings: MRI Cervical Spine: Alignment of the cervical spine is maintained with normal vertebral body and spinal cord signal intensity. There is a high attenuated lesion located on the anterior epidural surface that extends from C1-C4 with no evidence of spinal cord compression. Also noted is a moderate disc bulge at the C6-C7 level with mild compression of the anterior thecal sac and a mild disc bulge and small posterior osteophyte complexes at the C5-C6 level.

Diagnosis: Anterior epidural venous plexus enlargement

Discussion: The enlarged anterior epidural venous plexus was an incidental finding in this study and does not account for the patient's right leg weakness given its location and lack of spinal cord compression radiographically. The epidural venous plexus is an extensive valveless anastomotic vascular system that extends the full length of the vertebral column connecting the superior and inferior vena cava. The plexus is smallest in the cervical region and progressively enlarges as it traverses the lumbar region, with its largest network in L4-L5. It dramatically decreases in size at the sacral region. Epidural vein enlargement is a rare radiographical finding, and has not been significantly studied. It is generally seen alongside other vascular anomalies such as arteriovenous malformations, in the setting of IVC thrombosis or compression in which they serve as a collateral outflow pathway, or sequelae of compressive lesions in the spinal cord. Patients may present with radicular symptoms similar to disc herniation or spinal stenosis if the lesion compresses the spinal cord. For example a lesion in the lumbar region may produce sciatica or urinary retention. The differential diagnosis to consider includes an epidural abscess, hematoma, synovial cyst, or tumor. Treatment for epidural venous enlargement is decompressive laminectomy with or without resection of the enlarged venous plexus.

References:

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2. Groen RJ, Groenewegen HJ, van Alphen HA, Hoogland PV. Morphology of the human internal vertebral venous plexus: a cadaver study after intravenous Araldite CY 221 injection. Anat Rec. 1997 Oct;249(2):285-94. PMID: 9335475 [PubMed]
3. Paksoy Y, Gormus N. Epidural venous plexus enlargements presenting with radiculopathy and back pain in patients with inferior vena cava obstruction or occlusion. Spine (Phila Pa 1976). 2004 Nov 1;29(21):2419-24. PMID:15507805 [PubMed]