Evaluation of Intramedullary Spinal Cord Tumors in Children

Examination

Focality of signs is to be expected in the majority of cases, reflecting the benign nature of the majority of IMSCTs in children.  Concern for a malignant tumor should be raised when this is not the case.

• Asymmetrical motor examination: Asymmetrical motor function is age dependent but usually evident.  In older children one expects to find clear asymmetry in strength that may or may not be realized by the patient. In toddlers who are still walking, frequent falling to one side or loss of arm swing will be seen. In infants there will be an asymmetry in muscle tone. 

• Sensory asymmetry: Although sensory asymmetry is less common, it can be present to either touch or pain or both.  Dysesthesia may be elicited with touch. Signs of proprioceptive deficits may also be present. 
  
• Increased tone: Myelopathy is usually present when a benign tumor has been slowly growing in size. Passive ranging will elicit hypertonia that builds, and reflexes should be increased, with or without evidence of clonus.

Laboratory Tests

Standard preoperative laboratory tests are needed. No particular abnormalities are expected.

Radiologic Tests 

MRI

MRI with and without gadolinium enhancement is required. At a minimum, T1- and T2-weighted sequences should be obtained in the axial and sagittal planes (31). A gradient echo (GE) sequence is useful to show hemosiderin deposits, and FLAIR sequence can show subtle intramedullary lesions. 

• Eccentric tumors: Eccentric tumors are typical of astrocytomas, gangliogliomas, and other gliomas except ependymomas.
• Central tumors: Central tumors are typical of ependymomas.
• Cysts: Cysts are common with hemangioblastomas.
• Popcorn lesions: Popcorn lesions with hemosiderin halos are characteristic of cavernous malformations.

Nuclear Medicine Tests

No particular nuclear medicine tests are required, and one would expect no stereotypic finding.

Electrodiagnostic Testing

No electrodiagnostic test is indicated. Occasionally, these tests may have been done by others prior to the child being referred for neurosurgical evaluation.

• EMG: Not useful.
• NCS: Nerve conduction studies will show elevated H-reflexes for nerves synapsing in the cord below the level of the lesion.
• SEPs: SEPs will show slowing through the level of the lesion with delay in the cortical recordings.

Neuropsychological Testing

No preoperative neuropsychological testing is indicated.

Correlation of Tests

Congruency of the patient history, examination findings and MRI scan is expected. If congruency is not present, caution should be used at surgery with frozen biopsies being obtained prior to aggressive resection.