Can give me outline topic map in CNS pathology for FMGE exam??
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FMGE CNS pathology high yield topics exam 2024
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https://fmgeprep.com/fmge-subjects/pathology
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I now have enough content from the textbooks and FMGE-specific sources to compile a thorough, well-organized topic map. Here it is:
๐ง CNS Pathology - FMGE Topic Map (Outline)
Source: Robbins & Kumar Basic Pathology; Quick Compendium of Clinical Pathology 5th ed.; FMGE Prep Guide 2026
1. CONGENITAL MALFORMATIONS โญ
| Topic | High-Yield Points |
|---|---|
| Neural tube defects | Spina bifida (occulta, meningocele, meningomyelocele), anencephaly |
| Chiari malformations | Type I (tonsil herniation), Type II (with meningomyelocele + hydrocephalus) |
| Dandy-Walker | Absent/hypoplastic cerebellar vermis + posterior fossa cyst |
| Holoprosencephaly | Failure of prosencephalon division - associations with trisomy 13 |
| Lissencephaly | Absent gyri - smooth brain; ARX/LIS1 mutations |
| Hydrocephalus | Communicating vs non-communicating; causes |
2. CNS INFECTIONS โญโญโญ
Meningitis
| Type | Organisms | CSF findings |
|---|---|---|
| Bacterial | N. meningitidis, S. pneumoniae, neonates: E. coli, Listeria | Turbid, neutrophilic pleocytosis, โโ protein, โโ glucose |
| Viral (aseptic) | Enteroviruses, HSV-2 | Clear, lymphocytic, normal/mildly โ glucose |
| TB meningitis | M. tuberculosis | Lymphocytic, โ protein, โ glucose, "cobweb" clot |
| Fungal | Cryptococcus (HIV) | India ink positive; "soap bubble" lesions |
Brain Abscesses
- Polymicrobial; frontal lobe common
- Ring-enhancing lesion on MRI - key FMGE question
- Source: direct spread (sinusitis, otitis) or hematogenous
Encephalitis
- HSV encephalitis: temporal lobe hemorrhagic necrosis; Cowdry A inclusions
- Rabies: Negri bodies (hippocampus, Purkinje cells)
- CMV: periventricular calcification; "owl-eye" inclusions
- Progressive multifocal leukoencephalopathy (PML): JC virus; HIV patients; demyelination
Parasitic
- Neurocysticercosis: T. solium; "racemose" cysts; commonest seizure cause in endemic areas
- Cerebral malaria: ring hemorrhages; P. falciparum
- Toxoplasmosis: AIDS-defining; ring-enhancing lesion (basal ganglia)
3. CEREBROVASCULAR DISEASE โญโญโญ
Ischemic Stroke / Infarction
- Red (hemorrhagic) infarct: venous thrombosis or reperfusion
- Pale (white) infarct: arterial occlusion
- Watershed infarct: hypotension - "man-in-barrel" syndrome
- Lacunar infarcts: HTN; small penetrating arteries; internal capsule, basal ganglia
Hemorrhage
| Type | Key Features |
|---|---|
| Epidural hematoma | Arterial - middle meningeal artery; "lens-shaped" on CT; lucid interval |
| Subdural hematoma | Bridging veins; "crescent-shaped"; elderly/alcoholics |
| Subarachnoid hemorrhage | "Worst headache of life"; berry aneurysm rupture; xanthochromia |
| Intracerebral | HTN - putamen/external capsule #1 site; Charcot-Bouchard microaneurysms |
Aneurysms
- Berry (saccular): bifurcations of Circle of Willis; association with ADPKD, coarctation of aorta
- Mycotic: infective emboli
- Charcot-Bouchard: HTN; small penetrating arteries
4. CNS TUMORS โญโญโญ (Most High-Yield in FMGE)
Gliomas (WHO 2021 Classification)
Adult-type diffuse gliomas:
| Tumor | Grade | Molecular Marker | Key Features |
|---|---|---|---|
| Astrocytoma IDH-mutant | 2-4 | IDH1/2 mutation, ATRX loss, TP53 | "Glial fibrillary acidic protein (GFAP)+" |
| Oligodendroglioma IDH-mutant | 2-3 | IDH mutation + 1p/19q codeletion | "Fried-egg" cells; calcification |
| Glioblastoma IDH-wildtype | 4 | EGFR amplification, PTEN mutation, TERT promoter | Pseudopalisading necrosis; butterfly glioma |
Pediatric-type gliomas:
| Tumor | Site | Key Feature |
|---|---|---|
| Pilocytic astrocytoma | Cerebellum | KIAA1549-BRAF fusion; Rosenthal fibers; biphasic pattern |
| Diffuse midline glioma | Thalamus/pons/spinal cord | H3 K27-altered; DIPG in children |
| Ependymoma | 4th ventricle/spinal cord | Perivascular pseudorosettes; rod-shaped blepharoplasts |
| Medulloblastoma | Cerebellum (vermis) | Homer-Wright rosettes; seeds CSF early |
| Subependymal giant cell astrocytoma (SEGA) | Foramen of Monro | TSC1/TSC2 mutation; tuberous sclerosis |
Non-Glial Brain Tumors
| Tumor | Origin/Site | Key Feature |
|---|---|---|
| Meningioma | Arachnoid cap cells; falx/parasagittal | Psammoma bodies; NF2 mutation (60%); "dural tail" on MRI |
| Craniopharyngioma (adamantinomatous) | Rathke's pouch | CTNNB1 mutation; "machine oil" fluid; calcification |
| Craniopharyngioma (papillary) | Sellar/suprasellar | BRAF V600E mutation |
| Schwannoma | CN VIII (acoustic) | S-100+; NF2; bilateral = NF2 syndrome |
| Primary CNS Lymphoma | Periventricular | CD20+; large B-cell; ring-enhancing in immunocompromised |
| Hemangioblastoma | Cerebellum | VHL syndrome; cystic + mural nodule; stromal cells with lipid vacuoles |
Molecular Markers (VERY HIGH-YIELD for FMGE)
- IDH mutation โ better prognosis in gliomas
- 1p/19q codeletion โ oligodendroglioma diagnosis
- EGFR amplification, TERT promoter โ GBM IDH-wildtype
- BRAF V600E โ papillary craniopharyngioma, pleomorphic xanthoastrocytoma, ganglioglioma
- NF2 loss (merlin) โ meningioma, schwannoma
- VHL โ hemangioblastoma, clear cell RCC
5. DEMYELINATING DISEASES โญโญ
| Disease | Feature |
|---|---|
| Multiple Sclerosis | Plaques in periventricular white matter, optic nerve, spinal cord; shadow plaques (remyelination); Dawson fingers |
| Acute disseminated encephalomyelitis (ADEM) | Post-viral/vaccine; perivenous demyelination |
| Progressive multifocal leukoencephalopathy | JC virus; HIV/immunosuppression; asymmetric demyelination |
| Metachromatic leukodystrophy | Arylsulfatase A deficiency; sulfatide accumulation |
| Adrenoleukodystrophy | X-linked; very long chain fatty acids; ABCD1 gene |
| Krabbe disease | Galactocerebroside beta-galactosidase deficiency; globoid cells |
6. NEURODEGENERATIVE DISEASES โญโญ
| Disease | Pathology | Inclusions/Markers |
|---|---|---|
| Alzheimer's disease | Neocortical atrophy; hippocampus; neuritic plaques + NFTs | Amyloid (Aฮฒ) plaques, tau tangles; ApoE4 risk |
| Parkinson's disease | Depigmentation of substantia nigra; loss of dopaminergic neurons | Lewy bodies (alpha-synuclein) |
| Huntington's disease | Caudate atrophy; CAG repeat expansion (HTT gene); "boxcar" ventricles | - |
| ALS | Upper + lower motor neuron loss | TDP-43 aggregates |
| Frontotemporal dementia | Frontal/temporal atrophy | Pick bodies (tau) in Pick disease |
| Lewy body dementia | Diffuse cortical Lewy bodies | Alpha-synuclein; fluctuating cognition |
| Prion diseases (CJD) | Spongiform change; no inflammation | PrPSc (misfolded prion protein) |
| Friedreich's ataxia | Spinal cord + cerebellum degeneration | GAA repeat; frataxin deficiency |
7. CNS TRAUMA โญ
- Diffuse axonal injury: white matter shearing; immediate loss of consciousness; beta-amyloid precursor protein (APP) stain
- Contusion: cortical surface; "coup" and "contrecoup"
- Chronic traumatic encephalopathy (CTE): tau deposits; repeated trauma (boxers, NFL players)
- Spinal cord injury: central cord syndrome, Brown-Sequard, anterior cord syndrome
8. RAISED INTRACRANIAL PRESSURE & HERNIATIONS โญ
| Type | Structures Involved | Key Sign |
|---|---|---|
| Uncal (transtentorial) | Uncus โ CN III, PCA | Ipsilateral fixed dilated pupil |
| Tonsillar | Cerebellar tonsils โ foramen magnum | Respiratory arrest, "coning" |
| Subfalcine | Cingulate gyrus under falx | ACA compression |
| Central | Bilateral downward | Duret hemorrhages (midbrain/pons) |
9. CNS EDEMA โญ
| Type | Mechanism | Example |
|---|---|---|
| Vasogenic | BBB breakdown; extracellular | Tumors, abscess, hemorrhage |
| Cytotoxic | Intracellular Na/water accumulation | Ischemia, hypoxia |
| Interstitial (hydrocephalic) | CSF seeps into periventricular white matter | Obstructive hydrocephalus |
10. SPINAL CORD PATHOLOGY
- Syringomyelia: central canal expansion; cape-like loss of pain/temp
- Subacute combined degeneration: B12 deficiency; dorsal + lateral columns
- Tabes dorsalis: syphilis; dorsal columns + dorsal roots
- Anterior spinal artery syndrome: bilateral motor loss + pain/temp loss; proprioception spared
FMGE EXAM TIPS - CNS Pathology
| Must-Know Mnemonics / One-Liners |
|---|
| Pseudopalisading necrosis = GBM (IDH-wildtype, Grade 4) |
| Rosenthal fibers = Pilocytic astrocytoma (also seen in Alexander disease) |
| Psammoma bodies = Meningioma, papillary thyroid Ca, serous ovarian Ca |
| Fried-egg cells = Oligodendroglioma |
| Homer-Wright rosettes = Medulloblastoma, neuroblastoma |
| Flexner-Wintersteiner rosettes = Retinoblastoma, Ependymoma (true rosettes) |
| Perivascular pseudorosettes = Ependymoma |
| Ring-enhancing lesion = Abscess (smooth ring), Toxoplasmosis, PCNSL, GBM |
| Cowdry A inclusions = HSV encephalitis |
| Negri bodies = Rabies (hippocampus, Purkinje cells) |
| Owl-eye inclusions = CMV |
| Lucid interval = Epidural hematoma (middle meningeal artery) |
| Lewy bodies = Parkinson's, Lewy body dementia |
| Pick bodies = Pick disease (frontotemporal dementia) |
| KIAA1549-BRAF fusion = Pilocytic astrocytoma |
| BRAF V600E = Papillary craniopharyngioma, ganglioglioma, PXA |
| NF2 mutation = Meningioma (bilateral schwannoma = NF2 syndrome) |
| VHL gene = Hemangioblastoma |
| 1p/19q codeletion = Oligodendroglioma |
| H3 K27 mutation = Diffuse midline glioma (DIPG) |
Sources: Robbins & Kumar Basic Pathology; Quick Compendium of Clinical Pathology, 5th ed.; FMGE Prep Guide 2026 (fmgeprep.com)
This topic map covers the entire CNS Pathology syllabus for FMGE. Focus especially on tumor classification + molecular markers and classic histological inclusions - these generate the most questions. The WHO 2021 CNS tumor classification (IDH status, 1p/19q codeletion, H3 mutations) is now frequently tested in recent FMGE sessions.
Make a pdf contain all benign and malignant neoplasia and it markers & all diseases with its histopath, stains and IHC markers!!!
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mkdir -p /tmp/workspace/pathology-pdf && ls /tmp/workspace/pathology-pdf/
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