Intro to Neuropathology Flashcards
Any tumor that would “spill” into/adjacent to brain parenchyma would produce what?
a localized injury and astrogliosis
What are some histologic characteristics of Rosenthal fibers?
beaded sausage to cork screw shaped hyaline bodies of variable size, bright red on Masson trichrome, blue with Luxol fast blue stain
Rosenthal fibers are evident after long standing gliosis due to what?
pineal cysts, hemangioblastoma, spinal lesions, etc
What are eosinophilic granular bodies?
protein droplets seen in gangliomas and PXA, mark of slow growing low grade prognostically favorable tumors, PAS+
What are the surface markers for microglia?
CR3 and CD68 (same as peripheral macrophages)
What are the two types of cerebral edema?
Vasogenic and cytotoxic
What is vasogenic edema?
increased extracellular fluid due to BBB disruption and increased vascular permeability; fluid shifts from intravascular compartment to intercellular spaces; paucity of lymphatics impairs resporption of excess ECF; localized (adjacent to inflammation or neoplasm) or generalized; often follows ischemic injury
What are the characteristics of generalized cerebral edema?
flattened gyri, narrowed sulci, compressed ventricles; can lead to herniation
What happens to ventricular volume with hydrocephalus?
ventricular volume increases out of proportion to volume of sulci
The largest width of the frontal horns (FH) should be _____ than half of the internal skull diametric in ___ hydrocephalus
greater; true
What is the response to increased CSF?
Absorption of tranventricular and nerve root sleeves, dilation of frontal and temporal horns, elevation of corpus callosum, thinning of the cerebral mantle, stretching/perforation of septum pellucidum, enlargement of 3rd ventricle downwards, papilledema (increased ICP)
What is the pathogenesis of hydrocephalus/increased CSF?
- increased production of CSF due to choroid plexus papilloma (rare);
- obstruction due to intraventicular foramina (exudates/tumors/blood clots), congenital (stenosis/atresia), or secondary (tumors/hemorrhages/infections);
- decreased absorption due to outflow obstruction
What are causes of congenital hydrocephalus?
intrauterine infections (TORCH), genesis/atresia/stenosis, AVM, Arnold chiari malformation, Dandy Walker syndrome, cranial defects such as achondroplasia or craniostenosis
What are acquired causes for hydrocephalus?
infections (meningitis, meningoencephalitis, cysticercosis), mass lesions (neoplasms such as medulloblastoma or astrocytoma), inflammation from a brain abscess, post hemorrhage (IVH, SAH, injury), choroid plexus papilloma/carcinoma, sagittal sinus thrombosis, hypervitaminosis A, idiopathic
What are the features and sx of hypervitaminosis A?
softening of skull bones in infants and kids; blurred vision, bulging fontanelles, dizziness, alterations in alertness
What is communication hydrocephalus?
occurs when CSF is not absorbed properly at the dural sinus level thus ventricles tend to be symmetrically dilated; involves the leptomeninges but there is not a single point of obstruction
What can cause overproduction of CSF seen in communication hydrocephalus?
choroid plexus tumor, neurosyphilis or arachnoid fibrosis following meningitis
What is non-communicating hydrocephalus?
occurs if ventricular system is focally obstructed due to a mass in the 3rd ventricle or aqueductal stenosis
What is hydrocephalus ex-vacuo?
a compensatory increase in ventricular volume secondary to a loss of brain parenchyma; dilation of the ventricles occurs as well as shrinkage of brain substance due to frontal atrophy with increasing age, stroke or other injury, or chronic neurodegenerative dz such as Huntington or Alz; CSF pressure is normal;
Increased ICP is generally due to what?
generalized brain edema, expanding mass lesion (tumor, abscess, hemorrhage), or increased CSF volume
What is herniation?
increased pressure bestowing the compensatory ability of the venous system to compress and displacement of CSF –> tissue herniation past the rigid dural folds (falx and tentorium) or through the openings of the skull
What is a subfalcine (cingulate) herniation?
cingulate gyrus displaced under the falx (can compress the ACA and lead to infarcts)
What is a transtentorial (uncinated, uncal, mesial temporal) herniation?
medial aspect of the temporal lobe compressed against the tentorium; CN3 –> dilated pupil and impaired eye movement on the side of the lesion
What is a tonsillar herniation?
cerebellar tonsils displaced through the foramen magnum; life threatening due to respiratory and cardiac center compression
What are the signs and sx of increased ICP?
HA, change in behavior, N/V, lethargy, change in pupil reaction, upward gaze, false localizing signs (e.g. 6th nerve palsy), seizures, decreased coordination, ataxia, papilledema
What is a duret hemorrhage?
progression of transtentorial herniation often accompanied by secondary hemorrhagic lesions in the midbrain and pons
What is an infarct?
area of necrosis resulting from sudden insufficiency of arterial or venous blood supply
What is the characteristics of neurons during hypoxia?
neuronal loss, with the remaining neurons being shrunken, eosinophilic and/or pyknotic; can be seen in purkinje cells of the cerebellum and pyramidal cells of sommer’s sector
What is necrosis?
denaturation of intracellular proteins and enzymatic digestion of lethally injured cells; enzymes that digest the cells derived from the lysosomes of the dying ell themselves
What is liquefactive necrosis?
digestion of tissue into liquid mass, no architectural remnants; occurs in the CNS; possibly due to bacterial infections (purulent material)
CNS infarct results in what type of necrosis?
liquefactive; all other organs undergo ischemic coagulative necrosis (architecture remains)