Neuro-oncology (Intracranial and Spinal Tumors)
What the candidate must own
Know the WHO 2021 integrated diagnosis: histology plus molecular markers (IDH, 1p/19q codeletion, MGMT promoter methylation, H3 K27M, BRAF). Be able to describe the classic adult gliomas - astrocytoma IDH-mutant, oligodendroglioma IDH-mutant and 1p/19q-codeleted, glioblastoma IDH-wildtype - and the paediatric tumours (medulloblastoma subgroups, pilocytic astrocytoma, ependymoma). Understand the imaging signatures: ring enhancement with central necrosis for glioblastoma, calcification in oligodendroglioma, homogeneous enhancement of meningioma with a dural tail, and the distinction between intra-axial and extra-axial lesions. For spinal tumours, know the extradural (metastatic), intradural extramedullary (meningioma, schwannoma), and intramedullary (ependymoma, astrocytoma) compartments and their imaging behaviour.
Traps that appear in questions
- Assuming a ring-enhancing lesion is a tumour - abscess, demyelination, and radiation necrosis are classic mimics.
- Equating tumour grade with contrast enhancement; some low-grade tumours enhance and some high-grade ones do not.
- Forgetting that maximal safe resection with preservation of function is the goal, not gross total resection at all costs.
- Overlooking the need for molecular testing to guide prognosis and adjuvant therapy.
Rule of thumb
For any intracranial mass, first decide intra-axial versus extra-axial, then enhancement pattern, then molecular profile. Worked example: a 45-year-old with a calcified, non-enhancing frontal lesion and seizures - think oligodendroglioma; the confirmatory step is 1p/19q codeletion testing, which also predicts chemosensitivity.