[ Neurosurgery ] Brain tumor 1

Primary intra-axial brain tumor – most common

Glioma (GBM).

Primary extra-axial brain tumor – most common

Meningioma.

Brain tumors – most common type overall

Secondary (metastases).

Supratentorial tumors (more in adults) – manifestations

Early morning headache, seizures, and personality changes.

Infratentorial tumors (more in children) – presentation

More acute than supratentorial, with raised ICP (nausea, vomiting, headache, papilledema, blurred vision) and obstructive hydrocephalus (increased herniation risk).

Brain tumors – imaging

CT with or without contrast (initial), MRI with or without contrast (more accurate).

Infratentorial tumors – contraindicated procedure

Lumbar puncture.

Brain tumors – treatment

Surgery, radiotherapy, and chemotherapy, according to grade, stage, and type.

Diffuse infiltrative glioma – grade

Low grade (grade II) oligodendroglioma or astrocytoma.

Diffuse glioma – IDH classes

IDH-wild type and IDH-mutant type (most common).

IDH-mutant glioma – 1p/19q status

Co-deleted is oligodendroglioma, non-co-deleted is astrocytoma.

Oligodendroglioma – grade

Low grade (grade II).

Oligodendroglioma – key imaging feature

Most common intra-axial glial tumor with calcification, best seen on non-contrast CT.

Oligodendroglioma – main presentation

Seizures.

Oligodendroglioma – histology

Fried egg appearance.

Oligodendroglioma – treatment

Surgical resection.

Physiological intracranial calcification – sites

Choroid plexus, pineal gland, falx cerebri, tentorium, and basal ganglia.

Pathological intracranial calcification – causes

Meningioma, oligodendroglioma, craniopharyngioma, vascular lesions (aneurysm, AVM), and congenital infections (CMV, herpes, toxoplasmosis).

Diffuse astrocytoma (IDH-mutant) – MRI sign

T2-FLAIR mismatch, which helps distinguish it from oligodendroglioma.

GBM – grade

High grade (grade IV) astrocytoma.