Neuro-oncology
What you must own
Know the classification, behaviour and management principles of the common tumours. In adults: metastasis (most common), glioblastoma (IDH-wildtype, grade 4), lower-grade IDH-mutant glioma, meningioma, pituitary adenoma, primary CNS lymphoma. In children: pilocytic astrocytoma, medulloblastoma, ependymoma, craniopharyngioma, germ cell tumours.
Understand the WHO 2021 integrated diagnosis (histology plus molecular markers: IDH, 1p/19q, MGMT promoter methylation, H3K27M). Know the difference between intra-axial and extra-axial lesions, and how imaging features (dural tail, calcification, enhancement pattern) help.
Management: multidisciplinary discussion, maximal safe resection, adjuvant radiotherapy and chemotherapy (e.g. temozolomide with radiotherapy in glioblastoma), and steroid use for vasogenic oedema. Understand the concept of pseudoprogression (treatment-related imaging change) versus true progression.
Traps
Questions test that metastasis is the most common adult brain tumour and that primary CNS lymphoma can be steroid-sensitive (steroids may obscure diagnosis). Another trap: distinguishing pseudoprogression from progression, and knowing that MGMT methylation predicts better response to alkylating agents.
Rule of thumb
Extra-axial (meningioma, schwannoma) versus intra-axial (glioma, metastasis) is the first imaging decision; then grade by enhancement, necrosis, and molecular markers.
Worked example
An adult with a ring-enhancing lesion and known lung cancer: metastasis is most likely, but abscess and high-grade glioma remain differentials. Management starts with imaging and multidisciplinary review, not immediate biopsy.