Select the most likely diagnosis for these images of a 7-year-old boy.
- Ganglioglioma
- Ependymoma
- Medulloblastoma
- Astrocytoma
- Metastasis
Answer
Congratulations to all those who guessed Ependymoma. These are usually avidly contrast-enhancing tumors but lower-grade tumors can be non-enhancing, unlike Medulloblastoma which would always show heterogeneous contrast enhancement and would infiltrate the brainstem rather than pushing anteriorly. Ependymoma is iso- to hypo-intense on T1 and hyper-intense on T2. Ganglioglioma is a close differential but would not generally extend downwards till mid-spine.
Metastasis is uncommon in this age group. Astrocytoma is more common in the upper spine than ependymoma, but it would cause expansion of the cord and brainstem.