Spinal cord tumors are rare but clinically significant, causing progressive neurological deficits. MRI is the modality of choice for diagnosis, localization, and surgical planning.
📍 Classification of Spinal Cord Tumors by Location
- Extradural (most common, ~55%)
- Metastases, lymphoma, myeloma
- Nerve sheath tumors (schwannoma, neurofibroma)
- Meningioma
- Intradural–Extramedullary (~40%)
- Meningioma
- Nerve sheath tumors
- Drop metastases (from intracranial tumors like medulloblastoma, ependymoma)
- Intramedullary (~5%)
- Astrocytoma (Children > adults)
- Ependymoma (Adults > children)
- Hemangioblastoma
- Rare: ganglioglioma, oligodendroglioma
🔎 MRI Features
General Principles
- T1: tumor hypointense to isointense
- T2: hyperintense
- Post-contrast: variable enhancement
- Cord expansion: intramedullary lesions
- Associated features: syrinx, edema, cysts, hemorrhage
1. Extradural Tumors
- Most commonly metastases
- MRI: hypointense on T1, hyperintense on T2, variable enhancement
- Vertebral body destruction, soft tissue mass compressing cord
2. Intradural–Extramedullary Tumors
- Meningioma:
- Middle-aged women
- Iso- to hypointense on T1, iso-/hyperintense on T2
- Homogeneous enhancement, dural tail sign
- Nerve sheath tumors (schwannoma, neurofibroma):
- Well-defined, eccentric to cord
- T2 hyperintense, heterogeneous
- “Target sign” (neurofibroma), cystic degeneration (schwannoma)
3. Intramedullary Tumors
- Astrocytoma:
- Pediatric predominance
- Long-segment involvement, infiltrative, heterogeneous enhancement
- Ependymoma:
- Adult predominance
- Central, well-defined, expansile
- Homogeneous enhancement
- “Cap sign”: hemosiderin rim on T2/gradient
- Hemangioblastoma:
- Focal, enhancing nodule with cyst/syrinx
- Flow voids from feeding vessels
🧠 Teaching Points
- Location is key: extradural vs intradural–extramedullary vs intramedullary.
- Ependymoma vs astrocytoma:
- Ependymoma → central, well-circumscribed, cap sign, adults
- Astrocytoma → eccentric, infiltrative, children
- Always evaluate for skip metastases and CSF seeding (use contrast MRI whole neuraxis).
📊 Comparison of Common Spinal Cord Tumors (MRI Features)
| Feature | Meningioma | Schwannoma / Neurofibroma | Ependymoma | Astrocytoma |
|---|---|---|---|---|
| Location | Intradural–extramedullary | Intradural–extramedullary (eccentric to cord) | Intramedullary (central) | Intramedullary (eccentric) |
| Age | Middle-aged women | Adults, any age | Adults > children | Children > adults |
| T1 signal | Iso-/hypointense | Iso-/hypointense | Iso-/hypointense | Iso-/hypointense |
| T2 signal | Iso- to hyperintense | Hyperintense (may be heterogeneous) | Hyperintense, central | Hyperintense, often heterogeneous |
| Enhancement | Homogeneous, strong | Variable, often heterogeneous | Homogeneous | Patchy/heterogeneous |
| Special signs | Dural tail sign | “Target sign” (neurofibroma), cystic changes (schwannoma) | Cap sign (hemosiderin rim), polar cysts, syrinx | Long-segment expansion, infiltrative, syrinx |
| Cord effect | Compression, displacement | Compression, displacement | Central cord expansion, well-circumscribed | Diffuse cord expansion, poorly defined |
| CSF seeding | Rare | Rare | May occur (drop metastases) | Rare |
| Other features | Calcification may be present | May show dumbbell extension through foramina | Most common adult intramedullary tumor | Most common pediatric intramedullary tumor |
🧠 Teaching Nuggets
- Intradural–extramedullary → think meningioma or schwannoma.
- Intramedullary → adults → ependymoma; children → astrocytoma.
- Key MRI signs:
- Dural tail = meningioma
- Target sign = neurofibroma
- Cap sign = ependymoma
