Case of the Week
Section Editors: Matylda Machnowska1 and Anvita Pauranik2
1University of Toronto, Toronto, Ontario, Canada
2BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
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September 10, 2020
Idiopathic Thoracic Spinal Cord Herniation into a Vertebral Body
- Background:
- Idiopathic spinal cord herniation (ISCH) is a rare pathology caused by an anterolateral dural defect in the thoracic spine that typically occurs at T4–T7 and is thought to be of posttraumatic, postoperative, congenital, or postinflammatory origin.
- Scalloping in the adjacent vertebral body has occasionally been observed.
- Clinical Presentation:
- ISCH has been described in a wide age range (22–70 years).
- It has been described slightly more frequently in women, but with no definitive sex bias.
- The main clinical presentation is Brown-Sequard syndrome.
- Other symptoms include: gait disturbances, numbness and loss of temperature sensation in lower limbs, pain, and incontinence.
- Key Diagnostic Features:
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ISCH manifests itself with a segment of spinal cord parenchyma extending outside the dura, with ventral angulation and displacement of the spinal cord.
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Focal cord thinning may be present.
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Rarely, it may be associated with bone erosion, in which the spinal cord protrudes.
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- Differential Diagnoses:
- Lucent bone lesion: Lucent bone lesions that may appear in vertebrae include aneurysmal bone cysts, osteoblastoma, plasmacytoma, metastases, and simple bone cysts. A lytic bone tumor can be excluded by the presence of a wide cortical defect rather than cortical expansion.
- Intradural extramedullary cystic lesion: Imaging findings of ISCH are quite characteristic, but it may be necessary to exclude intradural extramedullary lesions, which cause anterior displacement of the spinal cord, such as epidermoid cysts, intradural arachnoid cysts, or cystic nerve sheath tumors. These can be excluded with high-resolution imaging or myelography to show the absence of an intradural extramedullary lesion compressing/displacing the cord.
- Treatment:
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Surgery is the treatment of choice to repair the dural defect.
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If there is a large bone cavity, as in the present case, it can be filled to prevent recurrence.
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