Chap 28 Morphology 3 Flashcards
Microscopic examination of Acute Disseminated Encephalomyelitis
- Myelin loss with preservation of axons in white matter
What is found in the lesions of the early stage of Acute Disseminated Encephalomyelitis?
- Neutrophils
What is found in the lesions of the later stage of Acute Disseminated Encephalomyelitis?
- Mononuclear infiltrates
What is the histologic similarities between Acute Necrotizing Encephalomyelitis and Acute Disseminated Encephalomyelitis?
- Perivenular distribution of demyelination throughout CNS
What are the histologic differences between Acute Necrotizing Encephalomyelitis and Acute Disseminated Encephalomyelitis?
- Acute Necrotizing damage is more severe
- Acute Necrotizing causes destruction of small blood vessels, disseminated necrosis of white and gray matter
- Acute Nec has fibrin deposition and many neutrophils
What is the gross cortical atrophy of the brain involved in AD?
- Widening of cerebral sulci in frontal, parietal, and temporal lobes
- Significant atrophy can cause compensatory ventricular enlargement
What structures are the first to atrophy in the early course of AD?
Hippocampus and amygdala
What is the major microscopic abnormality seen in AD?
Neuritic (senile) plaques and neurofibrillary tangles
What are neuritic plaques?
Collections of dilated neuritic processes around a central amyloid core surrounded by a clear halo
What is the dominant component of an amyloid plaque?
Ab peptide derived from APP protein
What are diffuse plaques?
Deposition of Ab peptides with the absence of neuritic processes
*Found in early stage of plaque development in AD
What are neurofibrillary tangles?
Tau-containing bundles of filaments in the cytoplasm of the neurons that displace or encircle the nucleus
What do neurofilbrillary tangles look like?
In pyramid cells- “flame” shapes
In rounder cells- basket weave of fibers
T/F Tangles are specific to AD
F- tangles are not specific to AD and can be found in other diseases as well
What is cerebral amyloid angiopathy?
An invariable accompaniment of AD
- When vascular amyloid Ab40 is present
What is the appearance of the atrophic regions of the cortex in FTLD-tau?
Neuronal loss, gliosis, and presence of tau-containing neurofibrillary tangles
What occurs in Pick Disease?
Brain shows pronounced asymmetric atrophy of the frontal and temporal lobes with sparing of the posterior 2/3s of superior temporal gyrus
What is the appearance of the gyri in Pick disease?
Wafer-thin gyri: “Knife-edge” appearance
Where is neuronal loss most severe in Pick Disease?
Outer three layers of the cortex
What is the appearance of the surviving neurons of Pick Disease?
Pick cells- swelling of neurons
Pick bodies- cytoplasmic filamentous inclusions that stain well with silver methods
What is the gross appearance of FTLD-TDP?
- Atrophy of frontal and temporal lobes
- Neuronal loss and gliosis
What is found in the inclusions in FTLD-TDP?
- TDP-43 is phosphorylated and ubiquitinated
Why does pallor of the substantia nigra occur in PD?
Loss of pigmented, catecholaminergic neurons
What are Lewy bodies?
- Single of multiple cytoplasmic, eosinophilic inclusions
- Have a dense core surrounded by a pale halo
What are the components of Lewy bodies?
Filaments and alpha-synuclein
What are Lew neurites?
Dystrophic processes that contain aggregated alpha-synuclein
What is found in the affected regions of progressive supranuclear palsy?
Globose fibrillary tangles in the neurons and glia
What is the appearance of the affected regions of corticobasal degeneration?
Loss of neurons, gliosis, and “ballooned” neurons
What is the most specific pathologic finding for CBD?
Clusters of tau-positive processes around astrocytes and the presence of tau-positive threads in gray and white matter
What is the appearance of the substantia nigra in CBD?
Loss of pigmented neurons, neuronal achromasia and tangles
Where does atrophy occur in the cerebellar form of multiple system atrophy?
Cerebellar peduncles, pons, medulla
Where does atrophy occur in the parkinsonian form of multiple system atrophy?
Substantia nigra and the striatum
What is the diagnostic element in multiple system atrophy?
Glia cytoplasmic inclusions that contain alpha-synuclein and ubiquitin
What is the appearance of the brain in Huntington Disease?
Brain is small and atrophy of the caudate nucleus and frontal lobe
What is seen microscopically with Huntington Disease?
Loss of striatal neurons and changes in the caudate nucleus
What structures are spared in the brain of a person with Huntington Disease?
- Diaphorase-positive neurons
- Large cholinesterase-positive neurons
What is the appearance of the spinal cord in Friedreich Ataxia?
- Loss of axons and gliosis in posterior columns, the corticospinal tract, and spinocerebellar tracts
- Degeneration of neurons in spinal cord, brainstem, cerebellum, and motor cortex
What is the appearance of the heart in Friedreich Ataxia?
- Enlarged with pericardial adhesions
- In autopsy, multifocal destruction of myocardial fibers with inflammation and fibrosis
Where are the abnormalities usually in Ataxia-Telangiectasia?
Cerebellum
What occurs in Ataxia-Telangiectasia?
- Loss of Purkinje and granule cells
- Degeneration of doral columns, spinocerebellar tracts, and anterior horn, and peripheral neuropathy
Where are telangiectatic lesions found in Ataxia-Telangiectasia?
- CNS, conjunctiva, and skin of the face neck and arms
What are amphicytes and when are they seen?
- Enlargement of the nucleus to 2-5 times normal size
- Seen in ataxia-telangiectasia
What structures are hypoplastic in ataxia-telangiectasia?
Lymph nodes, thymus, and gonads
What is the appearance of the anterior roots in ALS?
- Thin due to loss of LMN fibers and precentral motor in the cortex is atrophic
- Reduced number of anterior-horn neurons associated with reactive gliosis
What are Bunina bodies and when are the seen?
- Remnants of autophagic vacuoles
What occurs in the LMNs and UMNs in ALS?
LMN loss- skeletal muscles get degraded and show atrophy
UMN loss- degeneration of corticospinal tract causing volume loss and absence of myelinated fibers
What is the characteristic appearance of Wernicke encephalopathy?
Foci of hemorrhage and necrosis in mamillary bodies and walls of 3rd and 4th ventricle
What is the difference between early lesions and later lesions of Wernicke encephalopathy?
Early lesions- dilated capillaries with prominent endothelial cells
Later lesions- macrophages and cystic space with hemosiderin-laden macrophages
What lesions predominate in Korsakoff syndrome?
The later lesions of Wernicke encephalopathy (lesions infiltrated with macrophages and cystic space with hemosiderin-laden macrophages)
