# Intradural and Extradural Spinal Tumours

> Intradural and extradural spinal tumours for NEET-PG Orthopaedics: compartment classification, meningioma, schwannoma, ependymoma and dumbbell tumours.

- Canonical URL: https://prepelephant.com/topics/neet-pg/orthopaedics/intradural-and-extradural-spinal-tumours
- Exam / course: NEET-PG · Subject: Orthopaedics
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-14
- Last updated: 2026-10-14
- Reference basis: Apley's System of Orthopaedics and Fractures; Campbell's Operative Orthopaedics
- How to cite: "Intradural and Extradural Spinal Tumours", PrepElephant, https://prepelephant.com/topics/neet-pg/orthopaedics/intradural-and-extradural-spinal-tumours

## Direct answer

Intradural and extradural spinal tumours are classified by their position relative to the dura, and that position predicts both the clinical course and the surgical approach. Extradural lesions are mostly metastases, while meningiomas and schwannomas dominate the intradural extramedullary group and ependymomas the intramedullary one. Dumbbell tumours cross the neural foramen and need a combined approach.

## What you must remember

- **Extradural:** metastasis is the commonest spinal malignancy, with myeloma and lymphoma as other causes; pain and bony destruction are typical, and rapid deficit signals cord compression.
- **Intradural extramedullary:** meningioma and schwannoma are the commonest; both lie outside the cord but within the thecal sac.
- **Schwannoma origin:** arises from a dorsal, sensory nerve root and often extends laterally through the neural foramen.
- **Meningioma pattern:** typically a dural-based mass in the thoracic spine, with a female predominance.
- **Intramedullary:** ependymoma is the commonest intramedullary tumour in adults, often at the conus medullaris or filum terminale; astrocytoma is more typical in children.
- **Myxopapillary ependymoma:** a conus and cauda equina tumour seen in the lumbosacral region, a classic lesion in the exam.
- **Dumbbell tumour:** an intraspinal component and an extraspinal component joined through the neural foramen, most often a schwannoma or neurofibroma.
- **Imaging:** gadolinium MRI of the whole spine classifies the lesion, since the compartment narrows the differential.

## Sorting a spinal mass by compartment

A 50-year-old woman has thoracic pain and a spastic gait, and MRI shows a well-defined mass dorsal to the cord. The first question is compartment, because it narrows the differential before any biopsy or surgery.

| Compartment | Common tumours | Typical clue |
|---|---|---|
| Extradural | Metastasis, myeloma, lymphoma | Bone pain, rapid deficit, vertebral destruction |
| Intradural extramedullary | Meningioma, schwannoma, neurofibroma | Gradual deficit with the cord displaced |
| Intramedullary | Ependymoma, astrocytoma | Central cord expansion |
| Dumbbell | Schwannoma, neurofibroma | Foraminal widening with two components |

Extradural lesions usually destroy bone and cause pain, while intradural extramedullary tumours displace the cord and produce a slower deficit. Intramedullary tumours expand the cord itself, which makes complete resection without deficit harder.

Plain radiographs rarely settle the question, so contrast MRI comes before any biopsy or surgical plan. The surgical corridor differs between a dural-based mass and a lesion inside the cord, so the compartment should be named before the diagnosis. A well-circumscribed intradural mass on MRI narrows the answer far more than a vague description of the symptoms.

## What examiners test in spinal tumours

Examiners test whether you can sort a mass by compartment before naming it.

- **Trap:** calling every spinal mass in an adult a metastasis. **Correct:** meningiomas and schwannomas are common intradural tumours, so compartment sorting on MRI comes before any diagnosis.
- **Trap:** naming ependymoma for every intramedullary tumour. **Correct:** ependymoma predominates in adults, while astrocytoma is more typical of children, so age guides the differential.
- **Trap:** resecting a dumbbell tumour through laminectomy alone. **Correct:** the foraminal component needs a combined laminectomy and facetectomy or foraminal approach.

## Frequently asked questions

### Which spinal tumour is most common in the extradural compartment?

Metastasis is the most common spinal tumour in the extradural compartment, with breast, prostate, lung, kidney and thyroid among the usual primaries. Myeloma and lymphoma are other common extradural lesions of the spine.

### Which intradural extramedullary spinal tumours are most common?

Meningioma and schwannoma are the most common intradural extramedullary spinal tumours. Meningiomas are often seen in the thoracic spine of women, and schwannomas arise from dorsal nerve roots and frequently extend through the neural foramen.

### What is a dumbbell tumour of the spine?

A dumbbell tumour has an intraspinal component and an extraspinal component joined through the neural foramen, giving a dumbbell shape on imaging. Schwannomas and neurofibromas are the usual types, and resection typically needs a combined laminectomy and foraminal approach.

### Which intramedullary spinal tumour is most common in adults?

Ependymoma is the most common intramedullary spinal tumour in adults, and it often arises at the conus medullaris or filum terminale. Astrocytoma is more typical in children, so age at presentation is a useful clue when classifying an intramedullary tumour.

### What is the best imaging for classifying an intraspinal tumour?

Gadolinium-enhanced MRI of the whole spine is the investigation of choice for classifying an intraspinal tumour. It shows the compartment, the effect on the cord and the extent of any dumbbell component, which together narrow the differential.