Clival chordoma invading the hypoglossal canal

Erosive bone lesion involving the inferior most aspect of the clivus, at the region of the Basion/foramen magnum, with sclerotic and regular margins. Its soft tissue component that does not cause mass effect over the medulla oblongata. The remainder of the brain is unremarkable. Further evaluation with an MRI study is recommended. 

Sharply marginated, lobulated tumor extending from the distal lead tip of the clivus inferiorly to the level of the odontoid process showing slight and diffuse contrast enhancement. Its sharp margin niche on mismatched via the very sharp cut-off between normal bone and erect a bone in the CT scan, where sclerotic margins most likely indicate a slow growing tumor.

Note is again made of the well marginated lobulated mass from the tip of the clivus down to the level of the dens, in keeping with known chordoma. Slightly more heterogeneous appearance on T2 and post contrast imaging with mild size reduction in keeping with surgery and radiotherapy since 6.2.13. The expansile component protruding into the right peri-medullary cistern again touches the right vertebral artery, but with preserved CSF space, and no definite increased involvement of the right hypoglossal canal.

Midline inferior clival lesion extends inferiorly to the level of the foramen magnum, with right sided extension into expanded right hypoglossal canal. The increased size this mostly of the component bulging into the anterolateral aspect of the foramen magnum. This now displaces and distorts the medulla and vertebral artery. The mass is T2 hyperintense, T1 hypointense, with vivid enhancement. It contains stippled susceptibility artefact which may be due to calcification or blood product. 

Incidental note is made of two small developmental venous anomalies (DVA) in the left temporal lobe and left posterior frontal lobe. 

Fatty atrophy of the right hemi tongue compatible with hypoglossal nerve palsy. Mucosal thickening of paranasal sinuses with complete opacification of the left maxillary sinus which is small in volume. 

MICROSCOPIC DESCRIPTION: 1&2. Sections show a moderately cellular tumor, together with fragments of bone. The tumor is composed of cells with abundant clear to vacuolated cytoplasm set within myxoid stromal material. Tumor cells contain hyperchromatic, angulated nuclei with bland chromatin and inconspicuous nucleoli. No necrosis or mitosis are seen. There are areas of hemorrhage with hemosiderin laden macrophages and immature woven bone, consistent with remodeling. Immunohistochemical results show tumor cells stain: CKAE1/3+, EMA+ and S100+; consistent with chordoma.

DIAGNOSIS: 1&2. Brain, posterior fossa lesion: Chordoma.

Images and report courtesy from the Royal Melbourne Hospital Pathology Department.