21st June 2023

Overview of malignant spinal cord compression

Malignant spinal cord compression (MSCC), as the name suggests, is the compression of the spinal cord or cauda equina caused by a malignant process. Although more commonly referred to as ‘metastatic spinal cord compression’, there are several mechanisms by which compression can occur and is not always seen in the presence of metastatic disease.

• Direct invasion – a malignant tumour (either primary or secondary) directly invades into the spinal canal causing resultant compression of the cord/cauda equina.
• Vertebral collapse – a malignant process that causes a compromise in the integrity of a vertebra (typically the vertebral body) causing displacement into the spinal canal, resulting in compression. Again, this can be caused by invasion into the vertebrae, or secondary to a metastatic deposit. Bony metastases are radiologically characterised as sclerotic or lytic. Lytic metastases cause demineralisation of the bone and as such, present a higher risk of destabilisation. These should be differentiated from vertebral collapse secondary to osteoporosis as the approach to management will be different. Clinically, this can pose a challenge as a number of treatments can result in bone demineralisation e.g. aromatase inhibitors for breast cancer, LHRH analogues for prostate cancer and steroids in a variety of applications.
• ‘Spinal canal metastases’ – this describes an umbrella term of metastatic disease found within the canal and can be separated by the location within the canal.
  • Extradural – located outside of the dura mater of the spinal cord. This can be secondary to invasion originating from outside of the vertebral canal.
  • Dural/intradural – located within the dura mater. Less common but is seen in the context of ‘drop metastases’ from primary CNS tumours, above the metastasis.
  • Intramedullary metastasis – located within the spinal cord itself. Technically, this would not be classed as malignant spinal cord compression, but the patient may present and be managed in a similar fashion.