Intradural extramedullary metastases

Last revised by Daniel J Bell on 21 Apr 2023

Intradural extramedullary metastases are rare and account for approximately 5% of spinal metastases.

Please review leptomeningeal metastases (brain) for a general discussion focused on the brain's subarachnoid space involvement.

The age at presentation depends on tumor type. Metastases from central nervous system malignancies generally occur at a younger age.

Presentation is highly variable. As the most commonly affected site is the lumbosacral spine, symptoms and signs include back or radicular pain, weakness, paresthesias, gait disturbance, cauda equina syndrome and symptoms and signs of meningeal irritation.

In the pediatric population, the most common intradural extramedullary neoplasms are leptomeningeal metastases resulting from primary brain tumors whereas in adults non-CNS tumors are most commonly encountered. Multiple lesions are common.

Primary tumors include:

Plain films and CT are inadequate for the assessment of possible leptomeningeal metastatic disease, and in these cases, MRI is required.

MRI without contrast may be normal, and thus when suspected contrast should be administered. Typical signal characteristics include:

  • T1: thickened nerve roots or nodular lesions that are isointense with the spinal cord may be seen

  • T2: cord edema may be seen with more extensive disease, especially if there is an intramedullary component

  • T1 C+ (Gd)

    • enhancing tumor nodules on the spinal cord, nerve roots or cauda equina.

    • sugar coating” of the spinal cord and nerve roots

Prognosis is poor, and depends on the primary tumor. No surgical cure is possible, and treatment revolves around systemic chemotherapy and radiotherapy to the neuraxis (again, this depends on the primary tumor). 

If diffuse (sugar coating) consider:

If nodular (mostly at cauda equina) consider:

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