Age / Sex : 62 / M

Thoracic spinal cord herniation, idiopathic

Discussion

Findings:

1.     Focal thoracic spinal cord kink right anteriorly with atrophy

2.     Widening of posterior CSF space with flow artifact

3.     No evidence of abnormal signal intensity in bone marrow or spinal cord

4.     No evidence of HIV

Differential Diagnosis:

1.     Intradural arachnoid cyst

2.     Other intradural-extramedullary or extradural mass

Diagnosis:  Thoracic spinal cord herniation, idiopathic

Discussion:

1.     Pathogenesis: Still unkown
congenital, trauma, herniated disc, etc.

2.     22~71 years, slightly more common in male

3.     Common between T4~T7 (physiologic kyphosis)

4.     Symptom:
- Brown-Sequard syndrome in more than half of reported cases
- Other major symptoms: numbness, decreased temperature sensation in the legs, gait disturbance, pain, incontinence, etc.

5.     Flow artifact in widened CSF space can exclude closed cystic lesion (arachnoid cyst) or other solid mass.

6.     MR image is sufficient for diagnosis

References:

1. Parmar H, Park P, Brahma B, Gandhi D. Imaging of idiopathic spinal cord herniation. Radiographics 2008; 28:511-518