ABPath Neuropathology flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Brodmann area 4

Primary motor cortex located in the precentral gyrus; contains Betz giant pyramidal cells whose axons form the corticospinal tract.

Internal capsule posterior limb

White matter tract between thalamus and lentiform nucleus; carries corticospinal, corticobulbar, and sensory fibers and is a common site of lacunar infarction.

CA1 sector

Pyramidal cell region of the hippocampus most vulnerable to hypoxia and ischemia; also an early site of neurofibrillary tangle formation in Alzheimer disease.

Circle of Willis

Anastomotic ring at the brain base formed by anterior cerebral, internal carotid, posterior communicating, and posterior cerebral arteries with anterior communicating artery.

Glioblastoma definition

IDH-wildtype diffuse astrocytic glioma with necrosis or microvascular proliferation, or with TERT promoter mutation, EGFR amplification, or +7/-10.

Oligodendroglioma criteria

Diffuse glioma with IDH mutation and whole-arm 1p/19q codeletion; histology often shows uniform round cells with perinuclear halos and chicken-wire vasculature.

Lewy body

Eosinophilic neuronal cytoplasmic inclusion composed of alpha-synuclein and ubiquitin; found in substantia nigra and cortex in Lewy body disease.

Creutzfeldt-Jakob disease histology

Spongiform change with neuronal loss and gliosis; definite diagnosis requires demonstration of protease-resistant prion protein by immunoblot or immunohistochemistry.

Meningioma grade 2 criteria

Brain invasion, at least four mitoses per 10 high-power fields, or three of five atypical features including necrosis, sheet-like growth, and macronucleoli.

Alzheimer ABC score

Combined Braak tangle stage, Thal amyloid phase, and CERAD neuritic plaque score that assigns low, intermediate, or high Alzheimer disease neuropathologic change.

MGMT promoter methylation

Epigenetic silencing of the DNA repair gene MGMT that predicts improved response to temozolomide in glioblastoma and is assessed by methylation-specific PCR.

WHO CNS5 grading

Tumor grade integrates histologic features with molecular markers such as IDH status, 1p/19q codeletion, CDKN2A/B deletion, and H3 K27M mutation.

Intraoperative consultation timing

Frozen section diagnosis typically rendered within 20 to 30 minutes to guide surgical extent; final report usually issued within 24 to 48 hours.

CLIA proficiency testing

Regulatory requirement that laboratories demonstrate ongoing accuracy for immunohistochemistry and molecular assays through external proficiency surveys and documented validation.

Brain-only autopsy

Limited postmortem examination restricted to the central nervous system, performed with next-of-kin consent and often used for neurodegenerative disease research.

Peer review QA

Quality assurance process in which a sample of cases is re-reviewed by a second pathologist to identify diagnostic discrepancies and drive corrective action.

Muscle biopsy freezing

Skeletal muscle is snap-frozen in isopentane cooled by liquid nitrogen to preserve enzyme histochemistry; formalin fixation destroys ATPase and oxidative enzyme staining.

Sural nerve biopsy

Standard site for peripheral nerve sampling; tissue is divided for glutaraldehyde electron microscopy, paraffin histology, and teased fiber preparations.

Fiber typing ATPase

Myosin ATPase incubation at pH 9.4 stains type II fibers dark and type I light; preincubation at pH 4.3 reverses the pattern.

Retinoblastoma specimen handling

Enucleated eye is oriented at the optic nerve margin; fresh tumor is submitted for genetic testing and the globe sectioned to assess invasion.

CSF cytology sensitivity

Detection of leptomeningeal malignancy improves with repeat lumbar punctures and cytospin or cell block preparation rather than single samples.

Corneal button orientation

Excised corneal tissue must be oriented with marking sutures and assessed for endothelial cell density and stromal pathology before transplantation.

Gomori trichrome

Muscle stain that highlights mitochondria and ragged red fibers in red; useful in mitochondrial myopathy and nemaline rod evaluation.

Coagulative necrosis

Pattern of ischemic cell death in most solid organs preserving tissue architecture; brain instead undergoes liquefactive necrosis after infarction.

Congo red amyloid

Histochemical stain binding amyloid beta-pleated sheets, producing apple-green birefringence under polarized light; thioflavin T shows fluorescence.

Virchow triad

Three contributors to thrombosis: endothelial injury, abnormal blood flow or stasis, and hypercoagulability of the blood.

Granulomatous inflammation

Chronic inflammation with epithelioid histiocytes and multinucleated giant cells, seen in tuberculosis, sarcoidosis, and fungal infection.

Antigen retrieval

Heat or enzymatic pretreatment that unmasks epitopes cross-linked by formalin fixation, improving immunohistochemical staining sensitivity.

Grade versus stage

Grade describes tumor differentiation and biologic aggressiveness; stage describes anatomic extent of disease including nodal and distant spread.

Endogenous peroxidase

Intrinsic tissue peroxidase activity that can cause false-positive immunohistochemistry unless blocked with hydrogen peroxide before detection.

Fibroblast growth factor signaling

Receptor tyrosine kinase pathway regulating proliferation and angiogenesis; FGFR alterations occur in gliomas and other tumors and are therapeutic targets.

Middle cerebral artery embolism

Most common site of cerebral embolic occlusion, causing contralateral hemiparesis and aphasia when the dominant hemisphere is involved.