Central Nervous System Pathology

100 vocabulary flashcards covering cells, diseases, genetics, histologic features, and tumors discussed in the CNS pathology lecture.

Astrocyte

Star-shaped glial cell that contributes to the blood–brain barrier and is GFAP-positive on immunohistochemistry.

Blood-brain barrier

Selective barrier formed largely by astrocyte end-feet that protects the brain from circulating toxins and pathogens.

GFAP

Glial fibrillary acidic protein; immunohistochemical marker that stains astrocytes brown.

Microglia

Resident macrophages of the CNS responsible for phagocytosis of pathogens and damaged neurons.

Rod cells

Elongated activated microglia seen characteristically in neurosyphilis.

Neurosyphilis

Tertiary stage of syphilis affecting the CNS; features rod cells among other findings.

Neuronophagia

Phagocytosis of infected or damaged neurons by microglia, classically in polio and rabies.

Microglial nodule

Cluster of activated microglia commonly found in HIV-associated encephalitis.

Globoid bodies

Small round microglial inclusions characteristic of Krabbe disease.

Krabbe disease

Lysosomal storage disorder with globoid cell leukodystrophy caused by galactocerebrosidase deficiency.

Alzheimer's disease

Late-onset neurodegenerative disorder marked by memory loss, Aβ plaques, and neurofibrillary tangles.

Amyloid precursor protein (APP)

Protein on chromosome 21 whose abnormal cleavage yields Aβ; overexpressed in Down syndrome.

Chromosome 21

Location of the APP gene; trisomy leads to early-onset Alzheimer’s in Down syndrome patients.

Presenilin 1 (PS1)

Gene on chromosome 14 that increases γ-secretase activity, predisposing to early Alzheimer’s.

Chromosome 14

Genetic locus of the PS1 gene implicated in familial Alzheimer’s disease.

Presenilin 2 (PS2)

Gene on chromosome 1 whose mutation also enhances γ-secretase activity in Alzheimer’s.

Chromosome 1

Carries the PS2 gene associated with familial Alzheimer’s disease.

APOE4

Apolipoprotein E allele linked to increased risk and earlier onset of Alzheimer’s disease.

Bielschowsky stain

Silver stain that colors Alzheimer pathology black-brown, highlighting plaques and tangles.

Neuritic plaque

Extracellular core of Aβ amyloid surrounded by dystrophic neurites in Alzheimer’s disease.

Aβ amyloid

Peptide derived from APP cleavage that forms the core of Alzheimer’s neuritic plaques.

Neurofibrillary tangle

Flame-shaped intraneuronal aggregate of hyperphosphorylated tau protein in Alzheimer’s.

Hyperphosphorylated tau protein

Abnormal microtubule-associated protein forming neurofibrillary tangles.

Hirano body

Intracytoplasmic, needle-shaped actin-rich inclusion seen in Alzheimer’s disease.

Cerebral amyloid angiopathy

Deposition of Aβ in cerebral vessel walls, associated with Alzheimer’s and lobar hemorrhage.

Granulovacuolar degeneration

Intraneuronal cytoplasmic vacuoles with granules seen in the hippocampus of Alzheimer’s patients.

Parkinson's disease

Movement disorder due to loss of dopaminergic neurons in the substantia nigra pars compacta.

Substantia nigra

Midbrain structure rich in melanin; appears pale in Parkinson’s disease.

Dopaminergic neurons

Neurons producing dopamine; their loss underlies Parkinsonian motor symptoms.

Lewy body

Cytoplasmic inclusion with dense core of α-synuclein seen in Parkinson’s disease.

Alpha-synuclein

Protein aggregating within Lewy bodies in Parkinson’s and Lewy body dementia.

Huntington's disease

Autosomal dominant neurodegeneration from CAG repeats on chromosome 4 causing chorea and dementia.

CAG repeat

Trinucleotide expansion in HTT gene; the higher the repeats, the earlier Huntington onset.

Chromosome 4

Location of the HTT gene involved in Huntington’s disease.

Huntingtin protein

Mutant protein with expanded polyglutamine tract accumulating in the caudate nucleus.

Ubiquitin accumulation

Increase of ubiquitinated proteins observed in Huntington’s disease neurons.

Caudate nucleus

Basal ganglia structure that atrophies in Huntington’s disease.

Amyotrophic lateral sclerosis (ALS)

Neurodegenerative disease affecting both upper and lower motor neurons; features Bunina bodies.

Bunina bodies

Eosinophilic intracytoplasmic inclusions in anterior horn cells of ALS patients.

Brain tumor grading

WHO system ranking CNS tumors from Grade I (benign) to Grade IV (malignant).

Atypia

Cellular pleomorphism; one of four AMEN criteria for CNS tumor grading.

Mitosis (high proliferation)

Increased mitotic figures indicating higher-grade brain tumors.

Endothelial proliferation

Vascular change signaling aggressive CNS tumors in AMEN grading.

Tumor necrosis

Foci of dead tumor tissue; presence upgrades CNS tumors to Grade IV if combined with other factors.

Grade I tumor

Benign CNS neoplasm lacking atypia, mitosis, endothelial proliferation, and necrosis.

Grade IV tumor

Highly malignant CNS tumor exhibiting three or four AMEN criteria.

Pilocytic astrocytoma

Grade I cystic cerebellar tumor of children, often harboring BRAF mutations and Rosenthal fibers.

BRAF-KIAA fusion

Genetic alteration seen in many pilocytic astrocytomas.

BRAF V600E mutation

Oncogenic point mutation present in a subset of pilocytic astrocytomas.

Rosenthal fibers

Thick eosinophilic corkscrew glial filaments characteristic of pilocytic astrocytoma.

Cerebellar cystic tumor

Radiologic hallmark of pilocytic astrocytoma in children.

Glioblastoma

Grade IV astrocytoma in adults with poor prognosis, serpentine necrosis, and pseudopalisading cells.

Butterfly glioma

Glioblastoma that crosses the corpus callosum resembling butterfly wings on MRI.

Serpentine necrosis

Irregular necrotic areas with wavy borders typical of glioblastoma.

Pseudopalisading cells

Tumor cells lining necrotic regions in glioblastoma, resembling palisades.

Glomeruloid bodies

Tufts of proliferating capillaries in glioblastoma mimicking renal glomeruli.

IDH wild-type

Form of glioblastoma lacking IDH mutation; comprises ~90 % of cases and carries worse prognosis.

IDH mutant

Glioblastoma or oligodendroglioma with IDH mutation; generally better prognosis.

Oligodendroglioma

IDH-mutant, 1p/19q-codeleted cortical tumor with fried-egg cells and chicken-wire vessels.

1p/19q codeletion

Simultaneous loss of chromosome 1p and 19q arms conferring chemosensitivity in oligodendroglioma.

Fried egg appearance

Clear perinuclear halo around round nucleus in oligodendroglioma cells.

Chicken wire blood vessels

Delicate branching vasculature seen in oligodendroglioma histology.

Calcification in brain tumors

Radiologic feature common in craniopharyngioma, oligodendroglioma, and meningioma.

Ependymoma

Tumor of ependymal cell origin, most common in the fourth ventricle of children.

Fourth ventricle tumor

Typical location of pediatric ependymoma causing obstructive hydrocephalus.

Perivascular pseudorosette

Tumor cells arranged around blood vessels with intervening processes, seen in ependymoma.

RELA fusion ependymoma

Supratentorial ependymoma variant with RELA gene fusion on chromosome 11.

Supratentorial tumor

Lesion situated above the tentorium cerebelli, such as RELA-fusion ependymoma.

Medulloblastoma

Grade IV malignant cerebellar tumor of children displaying Homer Wright pseudorosettes.

Homer Wright pseudorosette

Tumor cells surrounding central fibrillary material; found in medulloblastoma and neuroblastoma.

Flexner-Wintersteiner rosette

True rosette with an empty lumen, characteristic of retinoblastoma.

Meningioma

Benign extra-axial tumor more common in females; progesterone receptor positive with whorls and psammoma bodies.

Progesterone receptor positive tumor

Hormone-responsive meningioma that may grow during pregnancy.

Whorling pattern

Concentric arrangement of tumor cells typical of meningioma histology.

Psammoma bodies

Lamellated calcific spherules seen in meningioma and other tumors.

Dural tail sign

MRI finding of thickened enhancing dura adjacent to a meningioma.

Atypical teratoid/rhabdoid tumor (AT/RT)

Highly malignant pediatric CNS tumor with SMARCB1/INI1 gene loss.

SMARCB1/INI1 mutation

Tumor suppressor gene loss defining atypical teratoid/rhabdoid tumor.

Dysembryoplastic neuroepithelial tumor (DNET)

Benign cortical epilepsy-associated lesion with floating neurons in mucin pools.

Floating neurons

Neuronal cells suspended in mucin characteristic of DNET.

Schwannoma

Peripheral nerve sheath tumor showing Antoni A/B areas and Verocay bodies; linked to NF2.

Antoni A area

Hypercellular, compact region in schwannoma histology.

Antoni B area

Loosely textured, hypocellular region in schwannoma histology.

Verocay body

Aligned nuclear palisades with central eosinophilic zone in schwannoma (Antoni A).

NF2 gene

Tumor suppressor on chromosome 22; mutations cause bilateral vestibular schwannomas and meningiomas.

Primary CNS lymphoma

Brain lymphoma, usually diffuse large B-cell type, often in immunocompromised patients.

Diffuse large B-cell lymphoma (DLBCL)

Histologic subtype of primary CNS lymphoma showing large malignant B cells.

Angiocentric pattern

Lymphoma cells clustering around blood vessels in CNS lymphoma.

Hooping pattern

Reticulin fibers encircling lymphoma cells seen in CNS lymphoma.

Diffuse midline glioma

Infiltrative tumor of brainstem or thalamus with H3K27M mutation and dismal prognosis.

H3K27M mutation

Histone H3 alteration defining diffuse midline glioma.

Prion disease

Transmissible spongiform encephalopathy marked by vacuolated cortex and kuru plaques.

Kuru plaque

Eosinophilic amyloid-like deposit found in prion diseases such as Kuru.

Congo red positivity (prion)

Apple-green birefringence of kuru plaques under polarized light after Congo red staining.

Craniopharyngioma

Suprasellar cystic tumor in children causing visual defects; shows wet keratin and peripheral palisading.

Peripheral palisading (craniopharyngioma)

Columnar epithelium lining cystic spaces in adamantinomatous craniopharyngioma.

Stellate reticulum

Loose network of cells in craniopharyngioma resembling enamel organ tissue.

Wet keratin

Compact, anucleate keratin seen as pink material in craniopharyngioma that can mimic machine oil.

Optic chiasm compression

Mass effect of craniopharyngioma leading to bitemporal hemianopia.

Chicken wire calcification

Lacy, thin calcification pattern characteristic of chondroblastoma but named analogously in pathology.