Intramedullary spinal tumors

Last revised by Raymond Chieng on 18 Apr 2023

Intramedullary spinal tumors are rare, representing 4-10% of all CNS tumors and <10% of all pediatric CNS neoplasms 5. They account for 20% of all intraspinal tumors in adults and 35% of all intraspinal tumors in children 8.

A long duration of symptoms prior to diagnosis is typical.

They can be classified according to many ways:

Intramedullary spinal neoplasms are more common in patients with neurofibromatosis:

  • ependymomas occur more often in patients with NF2

  • astrocytomas occur more often in patients with NF1

Approximately 70% of intramedullary tumors are associated with cysts 3. Two types of cysts are recognized:

  • tumoral (or intratumoral) cysts

    • contained within the tumor itself

    • typically demonstrate peripheral enhancement

    • may result from necrosis, fluid secretion, or degeneration of the neoplasm

    • need to be resected along with the solid portion of the tumor because there is a high likelihood of neoplastic cells within the cyst wall

    • occurs in association with the following proportion of tumors 5,6,9

      • spinal ganglioglioma: in 46%

      • spinal ependymoma: in 22%

      • spinal astrocytoma: in 21%

      • spinal hemangioblastoma: in 2-4%

  • non-tumoral (or reactive) cysts

    • occur rostral or caudal to the solid portion of the tumor

    • occur due to dilatation of the central canal

    • do not enhance

    • present in 60% of all intramedullary spinal tumors

    • may resolve once the neoplasm is resected

Syringomyelia occurs in approximately 50% of all intramedullary tumors but is most frequently associated with hemangioblastomas 3.

The presentation of intramedullary tumors depends on their size and location. The most common presenting symptoms include back/neck pain, radicular pain, weakness, paresthesia, gait disturbance and bowel and bladder dysfunction. Brown-Sequard syndrome may occur. An uncommon presentation is acute headache due to subarachnoid hemorrhage 8.

In children, progressive scoliosis may be seen. Motor regression and frequent falls may be the presenting features in young children 7.

Symptoms are usually slowly progressive. Due to their non-specific nature, the diagnosis is often delayed. An exception is intramedullary metastastases, which are diagnosed within one month of symptom onset in up to 75% of cases 6.

Widening of the interpedicular distance may be seen in less than 10% of cases

Generally not useful because bony changes are relatively rare.

  • the spinal cord can be enlarged

  • gradual subarachnoid space effacement

Three general characteristics of intramedullary neoplasms are recognized on MRI:

  • they cause either focal or diffuse spinal cord expansion

  • they produce high signal intensity on proton density and T2 weighted images

  • the vast majority show at least some contrast enhancement, in contrast to intracranial neoplasms, even low-grade intramedullary tumors enhance to some degree; however, the absence of enhancement does not exclude an intramedullary neoplasm in the presence of cord expansion 8,12

Various lesions may mimic intramedullary tumors. The differential diagnosis of intramedullary tumors includes:

  • vascular lesions

    • cavernous malformation (cavernoma)

      • rounded regions of heterogeneous signal intensity on T1 and T2 weighted images due to blood

      • products of varying ages (“popcorn appearance”)

      • low signal intensity rim on T2 weighted images (hemosiderin)

      • hypointense “blooming” on gradient echo sequences (hemosiderin)

      • may demonstrate minimal enhancement on post-contrast images

      • minimal cord expansion or edema unless there has been recent hemorrhage

    • dural arteriovenous fistula (DAVF)-(type I AVM) 

      • spinal cord may be normal size or enlarged

      • hyperintense on T2 weighted images (due to edema)

      • prominent vessels (flow voids) are usually present on the posterior aspect of the cord

      • variable enhancement on post-contrast images

      • typically located in the dorsal aspect of the lower thoracic cord and conus medullaris

    • spinal cord infarction 

      • spinal cord is usually enlarged

      • hyperintense on T2 weighted images and DWI

      • post-contrast enhancement may or may not be present (enhancement is usually present in the subacute stage)

      • signal intensity abnormality may be limited to the central grey matter or may involve most of the cross sectional area of the cord

      • signal abnormality typically extends over multiple vertebral body segments

      • can occur at any location in the cord but has a propensity for the upper thoracic or thoracolumbar regions

      • vertebral body T2 hyperintensity may occasionally be seen (due to concomitant infarction)

  • inflammatory lesions

    • demyelination (e.g. multiple sclerosis)

      • usually no spinal cord enlargement (enlargement is seen in 6-14% cases) 4

      • plaques are generally shorter than two vertebral body segments in length and involve less than half the cross-sectional area of the cord

      • characteristically peripherally located in the dorsal and lateral columns

      • isointense to hypointense on T1 weighted images (unlike brain plaques, cord plaques may not be visible as areas of hypointensity on T1 weighted imaegs)

      • hyperintense on T2 weighted images

      • signal abnormality is typically poorly marginated

      • plaque enhancement correlates with acute lesion activity (usually lasts less than two months)

      • in most patients additional lesions of variable enhancement are present in the brain and spinal cord (MS is solely confined to the spinal cord in 5-24% of patients 4)

    • transverse myelitis

      • variable enlargement of the spinal cord

      • hyperintense on T2 weighted images and iso- or hypointense on T1 weighted images

      • variable enhancement patterns (none, diffuse, patchy, peripheral)

      • lesions commonly extend for 3-4 spinal segments

      • lesions typically occupy greater than two thirds of the cross-sectional area of the cord

      • acute clinical course

    • spinal cord abscess 

      • core is hypointense on T1 weighted images and hyperintense on T2 weighted images

      • rim enhancement

      • cord expansion

      • may show restricted diffusion on DWI

      • may have adjacent vertebral or disc abnormalities

    • spinal cord tuberculoma

  • spinal cord contusion (acute)

    • isointense to hypointense on T1 weighted images, hyperintense on T2 weighted images

    • cord swelling

    • usually associated with other spinal injuries (osseous, disc, vascular)

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