Into what useful compartments / regions are spinal tumours usually grouped?
The relationship of the mass to the cord is of prime importance and typically two compartments are considered: intramedullary (ie within the cord), intradural extramedullary (ie. within the theca but outside of the cord). Additionally the cauda equina region is often considered separately as a number of lesions are particular to it.
In terms of the above classification, how would you describe this lesion?
This is an intramedullary lesion.
In addition to being intramedullary, what is important not note in regards to its location within the cord?
This lesion is located centrally within the cord (rather than eccentric or exophytic).
What prominent feature is seen below the mass, best appreciated on T2 sagittal images?
A low signal region, known as a hemosiderin cap.
What is the most likely diagnosis?
By far the most likely diagnosis is that of an ependymoma.
There is a 9 x 11 x 20 mm intramedullary mass in the upper cervical spinal cord. It is centrally located and extends between C2/3 and mid C4 levels. Associated cord expansion is noted.
Pre-contrast, the mass shows heterogeneous high T2 signal and T1 signal slightly less than that of spinal cord. There is an associated tumour syrinx extending between C1/2 and the lower C4 vertebral levels (37 mm craniocaudally), at the inferior aspect of which there is low T2 signal compatible with a "hemosiderin cap". The mass shows avid, homogeneous enhancement.
The remainder of the cervical spinal cord is normal in signal and calibre. The cervico-medullary junction is normally positioned. Posterior disc-osteophyte complexes at C5/6, C6/7, and C7/T1 mildly narrow the central vertebral canal. The neural exit foramina are adequate.