Fact-sheet: Astrocytoma of spinal cord
Updated on 09/17/2021 at 12:16 PM
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Definition
Intramedullary tumors account for 5% of primary central nervous system tumors and 30% of intradural intraspinal tumors.
Astrocytomas have the same prevalence as ependymomas.
Intramedullary tumors are most commonly seen in young adults, with a mean age of 30 years for astrocytomas.
Clinical features
They predominate in the cervicothoracic spinal cord (80%), extending on average over 6 spinal cord segments.
The initial presenting symptom is often pain ++++
All the usual signs of spinal cord involvement may be seen:
- motor deficit in the lower limbs (fatigability on walking, difficulty standing, limping, instability, weakness in a lower limb) and in the upper limbs (clumsiness of a hand...).
- subjective sensory disturbance (paresthesias, tightness sensation...) and/or objective sensory disturbance (sensory level).
- sphincter disturbances (dysuria, constipation, genital disorders).
CT
Allows the detection of cystic lesions or contrast enhancement, but is insufficient prior to treatment and for follow-up.
MRI
Key examination for diagnosis, preoperative work-up, and post-treatment follow-up.
1. T1-weighted sequences: The presence of an intramedullary tumor widens the spinal cord, which is enlarged over one or more levels; the tumor is hypointense relative to the spinal cord.
2. T2-weighted sequences: The solid portion of the tumor is most often hyperintense due to increased hydration, but hypointense areas may also be present, sometimes related to chronic bleeding (hemosiderin deposits, a breakdown product of hemoglobin). Cysts are always hyperintense.
3. After gadolinium injection: Intravenous gadolinium injection reveals, in the majority of cases, contrast enhancement of variable homogeneity, allowing clear delineation of the solid tumor component from the adjacent spinal cord and neighboring cysts.
Classification
These tumors have been classified into 4 grades of increasing malignancy (KERNOHAN, 1952), based on cellularity, the presence or absence of cytonuclear atypia, neovascularization, and areas of necrosis.