Spinal metastasis is a vague term that can be variably taken to refer to metastatic disease to any of the following:

• vertebral metastases (94%)

  • may have epidural extension

• intradural extramedullary metastases (5%)

• intramedullary metastases (1%)

Each of these are discussed separately. Below are some general remarks on metastatic disease to the spine, theca and cord.

Epidemiology

Approximately 90% of all spinal (cord and vertebral) neoplasms are considered metastatic in origin.

Clinical presentation

The presentation can be highly variable. Sudden onset development of the Brown-Sequard syndrome in patients with known metastatic cancer has been described as a presenting feature ^6-8.

Pathology

The spread of malignant cells to the region is variable and includes:

• haematogenic: arterial or venous

  • Batson venous plexus

• direct invasion: typically of paraspinal, retroperitoneal of pulmonary malignancies

• lymphatic: along the root sleeves

• subarachnoid: intracanalicular seeding of primary and secondary CNS neoplasms

As the vast majority of metastases to the region are to bone, this is reflected in the primaries which are encountered. Having said that breast cancer, lung cancer and melanoma are also relatively common sources of intradural disease.

Primaries include:

• breast: 22%

• lung: 15%

• prostate: 10%

• lymphoma: 10%

• kidney: 7%

• gastrointestinal tract: 5%

• melanoma: 4%

• unknown: 4%

• others: 24%

Differential diagnosis

For extradural lesions consider:

• spinal schwannoma/neurilemmoma

• spinal neurofibroma

• extradural cysts

  • developmental 

  • acquired: degenerative, infectious, traumatic/iatrogenic

For intradural extramedullary lesions consider (see also leptomeningeal metastases):

• if diffuse (sugar coating)

  • meningoradiculitis

  • arachnoiditis

• if nodular (mostly at cauda equina)

  • spinal meningioma

  • spinal neurilemmoma/schwannoma

  • leptomeningeal (pial) lipoma

  • post-arachnoiditic adhesions

  • drop metastases from CNS primaries

    • ependymoma

    • astrocytoma

    • oligodendroglioma

    • glioblastoma

    • choroid plexus tumours

    • germ cell tumours

    • medulloblastoma (PNET)

For intradural intramedullary lesions consider:

• inflammatory lesions (transverse myelitis)

• developmental lesions (intramedullary lipoma, syringomyelia)

• primary spinal cord tumours

  • ependymoma

  • astrocytoma

  • haemangioblastoma

See also

• vertebral metastases

• neoplasms of the spinal canal