In what compartment is the main abnormality located?
This is a difficult lesion to interpret. Clearly there is an extramedullary component, however whether this is an extramedullary process with resultant intramedullary change (oedema) or an intramedullary lesion which is exophytic cannot be determined.
What is the differential diagnosis?
If the T3 lesion is intramedullary, then an astrocytoma with a cystic component or syrinx with subarachnoid seeding is favoured over that of an ependymoma or haemangioblastoma. If the T3 lesion is intradural extramedullary, then metastasis from a non-intracerebral source or lymphoma needs to be considered, although both usually demonstrate more vivid enhancement and a cystic component would be unusual unless it is loculated CSF. A non neoplastic cause such as spinal sarcoidosis is also a possibility.
Partially cystic/solid lesion is identified at the T3 level. This lesion appears intradural extramedullary on the sagittal sequence but appears more intra-medullary on axials appearing to be centered posteriorly within the cord and eccentrically expands the cord at this level. The lesion extends a vertical length 1 vertebral body height. Central cystic component measures 1 cm. The solid component more inferiorly demonstrates diffuse mild homogeneous enhancement. No blood product seen on T2. No flow voids.
Multifocal slightly T1 hyperintense to cord, mildly enhancing soft tissue nodules also extend along the entire length of cord in the subarachnoid space. There is also diffuse mild leptomeningeal enhancement along the spinal cord.