Neuro-oncology
Core concepts
Know the WHO grading and molecular markers that drive prognosis and treatment: IDH mutation (favorable), 1p/19q codeletion (oligodendroglioma, chemosensitive), MGMT promoter methylation (temozolomide response in glioblastoma), and EGFR/PTEN alterations. Understand the standard of care for glioblastoma (maximal safe resection, radiation with concurrent and adjuvant temozolomide) and the role of extent of resection. Distinguish intra-axial from extra-axial tumors and their imaging signatures (ring enhancement, edema, dural tail for meningioma). Know metastatic disease epidemiology (lung, breast, melanoma) and when to use whole-brain radiation vs stereotactic radiosurgery vs surgery. Understand pituitary adenoma endocrine syndromes and the transsphenoidal approach. Recognize the difference between tumor progression and pseudoprogression (treatment-related imaging change).
Traps
Questions test whether you know that IDH status can override histologic grade in prognosis. A frequent trap is calling a ring-enhancing lesion a tumor when it could be an abscess (restricted diffusion on DWI). Another is confusing pseudoprogression with true progression early after chemoradiation. Beware assuming all meningiomas need resection - asymptomatic ones may be observed.
Worked rule of thumb
A newly diagnosed ring-enhancing intra-axial mass with restricted diffusion and fever should prompt abscess workup before assuming high-grade glioma. For glioblastoma, maximal safe resection followed by chemoradiation with temozolomide is standard, and MGMT methylation predicts better temozolomide response.