STEPTRACKERNERVOUS SYSTEM + ONCOLOGY | PATHOLOGY + GENETICS | HIGH-YIELD REVIEW

Adult Brain Tumors

Most adult tumors sit above the tentorium — metastases first, then the gliomas, meningiomas and schwannomas, each with a signature look.

FOCUS ON
Metastases are the most common brain tumors (lung, breast, melanoma, kidney), multiple, at the gray–white junction. Glioblastoma: hemispheric, crosses the corpus callosum, pseudopalisading necrosis, GFAP. Meningioma: dural-based, women, psammoma bodies. Schwannoma: CN VIII at the cerebellopontine angle, S100. Oligodendroglioma: fried-egg cells, calcified, 1p/19q.
TUMOR
ORIGIN · GENETICS
FEATURES · HISTOLOGY
CLUE
Metastases
most common
Lung (most), breast, melanoma, kidney, colon
Multiple well-circumscribed lesions at the gray–white junction; edema
Hemorrhagic: melanoma, RCC, choriocarcinoma, thyroid
Glioblastoma
most common primary malignant
Grade 4 astrocytoma, IDH-wildtype; EGFR amplification, PTEN, TERT
Cerebral hemisphere; crosses the corpus callosum ("butterfly"); ring enhancement; pseudopalisading necrosis, microvascular proliferation
GFAP ⁺ · median survival ~15 months · temozolomide (better if MGMT methylated)
Diffuse astrocytoma
IDH-mutant astrocytoma (grade 2–4); ATRX, TP53
Younger adults; infiltrative, nonenhancing early; seizures
Progresses to higher grade
Oligodendroglioma
IDH-mutant + 1p/19q codeletion
Frontal lobe; seizures; calcifications; "fried egg" cells with "chicken-wire" capillaries
Slow, chemosensitive, better prognosis
Meningioma
most common primary (benign)
Arachnoid cap cells; NF2, prior radiation; progesterone receptor ⁺
Women; extra-axial, dural-based with "dural tail"; compresses rather than invades; seizures, focal signs
Whorls + psammoma bodies
Vestibular schwannoma
Schwann cells of CN VIII; bilateral = NF2
Cerebellopontine angle: unilateral sensorineural hearing loss, tinnitus, imbalance; later CN VII and V
S100 ⁺ · Antoni A (Verocay bodies) + Antoni B
Hemangioblastoma
Stromal cells + capillaries; VHL
Cerebellum (and retina, cord); cystic with nodule
Makes EPO → polycythemia
Primary CNS lymphoma
Diffuse large B-cell lymphoma; EBV in AIDS; also elderly immunocompetent
Single (AIDS) or multiple periventricular enhancing lesions; may "melt" with steroids
High-dose methotrexate
Pituitary adenoma
Anterior pituitary
Bitemporal hemianopia, hormone excess or deficiency
Detail: 15.01
Spinal ependymoma (adult)
Ependymal cells; NF2
Intramedullary cord tumor; myxopapillary type at filum terminale
Perivascular pseudorosettes
Clinical presentation
Mass effect, irritation, edema
New seizures in an adult, progressive focal deficit, headache worse lying down, personality change
New seizure after 40 → image for tumor

Mechanism — sorting gliomas

Diffuse glioma
→
IDH status
→
IDH-wildtypeGlioblastoma, older, aggressive
IDH-mutant
→
1p/19q codeletedOligodendroglioma
Intact, ATRX lossAstrocytoma

IDH mutation produces 2-hydroxyglutarate (an oncometabolite) and predicts longer survival.

Adult tumors at a glance

TUMOR
LOCATION
HISTOLOGY
MARKER
Glioblastoma
Hemispheres, corpus callosum
Pseudopalisading necrosis
GFAP
Oligodendroglioma
Frontal lobe
Fried egg, chicken wire
1p/19q
Meningioma
Dura, convexities
Whorls, psammoma
EMA, PR
Schwannoma
CP angle
Verocay bodies
S100
Hemangioblastoma
Cerebellum
Foamy cells + capillaries
Inhibin
CNS lymphoma
Periventricular
Angiocentric B cells
CD20

How it's tested

COMMON CONFUSIONToxoplasmosis vs CNS lymphoma in AIDS: multiple ring lesions with positive Toxo serology → treat Toxo; single periventricular lesion with EBV in CSF → lymphoma.
THE TRAPMultiple brain masses in an adult are metastases until proven otherwise — look for the primary (start with the lungs).
YOUR APPROACHSingle vs multiple → intra- vs extra-axial → location → age and syndrome (NF2, VHL, AIDS) → histology and marker.

If you see… think…

Several masses at the gray–white junction in a smoker → metastases (lung)
Butterfly mass crossing the corpus callosum with central necrosis → glioblastoma
Necrosis surrounded by lined-up tumor cells → pseudopalisading (GBM)
Calcified frontal tumor, new seizures, fried-egg cells → oligodendroglioma
Dural-based mass with a tail in a woman → meningioma
Whorled cells with psammoma bodies → meningioma
Unilateral hearing loss and tinnitus, CP angle mass → vestibular schwannoma
Bilateral acoustic schwannomas → NF2
Cerebellar cystic tumor with polycythemia → hemangioblastoma (VHL)
AIDS patient, single periventricular lesion, EBV in CSF → primary CNS lymphoma