Based on CT and MRI, what are possible differential diagnosis?
The imaging appearances are those of a tumour centred in the midline inferior portion of the clivus with a bright T2 signal, chordoma is favoured. Chondrosarcoma is less likely by the lack of matrix calcification, tumour centred in the midline, and a more homogeneous enhancement. Lymphoma is less probably because of the lack of a vivid enhancement. Ecchordosis physaliphora would no present with prominent enhancement soft tissue component. Meningioma would be expected to have a more vivid enhancement, and the bone invasion pattern is less typical for this condition. A solitary plasmacytoma could be considered, but less likely in this age group.
Sharply marginated, lobulated tumour 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 tumour.