Introduction to Clinical Neuropathology

The objectives of the neuropathologic examination are twofold: First, to identify and localize any lesion(s), interpret histologic changes and ultimately, formulate a diagnosis. Second, to correlate the location and histopathologic features of the lesion(s) with the clinical presentation. Fulfilling these goals requires familiarity with the anatomy and histology of the nervous system. For this purpose, photographs of representative brain and spinal cord slices and myelin-stained sections are provided (Figs. 1.1 through 1.5).

Knowledge of the normal structure of neural tissue enables the student to recognize pathologic alterations. Thus, Chapter 2 gives a brief description of the histology of neural tissue components, along with their pathologic reactions.

The histologic examination requires, in addition to conventional stains, the application of specific stains for each constituent of the neural tissue: neuron, axon, myelin, glial cells, blood vessels, and meninges. Familiarity with staining methods is necessary to select the appropriate stains for the study of a particular disease. Histochemical stains are valuable for the study of neurometabolic diseases, and immunohisto-logic stains are essential for diagnosing tumors and defining neurodegenerative diseases (Tables 1.1 through 1.3). Electron microscopic examination is performed to define tumors and delineate inherited metabolic diseases.

The examination of the histologic sections begins first by identifying the pathologic alterations of each tissue component involved, then combining them into an orderly whole—that is, formulating a diagnosis. The final correlation of the pathologic features with the clinical features becomes a learning experience.

H sad of Caudate Fornix Puta m en

Callosum Fornix Head of Caudate

H sad of Caudate Fornix Puta m en

Label The Sheep Brain

Temporal Insula Horn

Pallidum

Anterior Commissure—¡ '— Middle Cerebral Artery Pulamen Fornix Thalamus Callosum Mammillary Body

Thalamus

Temporal Insula Horn

Pallidum

Anterior Commissure—¡ '— Middle Cerebral Artery Pulamen Fornix Thalamus Callosum Mammillary Body

Pallidum Insula

Subthalamic Uncus Nucleus

Callosum Fornix Head of Caudate

Thalamus

Internal Capsule And Optic Tract

Pul amen

Pallidum

Internal Capsule

Mammlllary Body

3rd Optic Tract Ventricle

Amygdala

Pul amen

Pallidum

Internal Capsule

Mammlllary Body

3rd Optic Tract Ventricle

Amygdala n Ruber

Subthalamic Uncus Nucleus n Ruber

Corticospinal Tract Substantia Nigra
Hippocampus— Substantia Nigra Lateral Geniculate Body

FIGURE I.I

Transverse slices of the brain.

Head of

Insula Frontal Horn Caudate Putamen

Carotid

Uncus Optic Nerve Artery Amygdala

Pallidum

Medial Geniculate Body

Temporal Horn

Head of

Insula Frontal Horn Caudate Putamen

Pallidum

Medial Geniculate Body

Temporal Horn

Medial Geniculate Body

Internal Capsule

Pedunculus

Lateral Geniculate Body

Aqueduct n Ruber Chiasma Optic Tract

Internal Capsule

Pedunculus

Lateral Geniculate Body

Carotid

Uncus Optic Nerve Artery Amygdala n Ruber Chiasma Optic Tract

Lateral Geniculate Body

Basilar Pontine Brachium Pontine Artery Tegmentum Conjunctivum

Tectum Substantia Lateral Aqueduct Nigra Geniculete

Body

Aqueduct

Basilar Pontine Brachium Pontine Artery Tegmentum Conjunctivum

Tectum Substantia Lateral Aqueduct Nigra Geniculete

Body

FIGURE I.2

Horizontal slices of the brain.

Tectum Tegmentum

FIGURE 1.3

Transverse slice of the cerebellum.

FIGURE 1.3

Transverse slice of the cerebellum.

TABLE 1.1.

Common Neurohistologic

Stains

Tissue Components

Stains

Neurons/glial nuclei

Nissl: thionin, toluidine blue

Kluver-Barrerra: cresyl violet

Nerve fibers —

Bielschowsky: silver nitrate

Neurofibrillary tangles^;;;;:

-Bodian: protargol

Neuritic plaques

Gallyas: silver nitrate

Glees and Marsland: silver

nitrate

Myelin

Woelcke: iron hematoxylin

Loyez: iron aluminum

Kluver-Barrera: Luxol fast blue

Neuron/myelin

Kluver-Barrera: Luxol fast

blue-cresyl violet

Nerve fiber/myelin

Holmes

Astrocytes

Cajal: gold chloride

Hortega: lithium carbonate

Holzer: crystal violet

Phosphotungstic acid/

hematoxylin (PTAH)

Oligodendrocytes

Penfield: silver nitrate

Microglia

Hortega: silver carbonate

Meninges/blood vessels

van Gieson

Masson: trichrome

Reticulin fibers

Gomori: silver nitrate

Elastic fibers

Verhoeff: hematoxylin

General stain

Hematoxylin-eosin

Media! Longitudinal

Media! Longitudinal

Spinal Cord Stained With Toluidine Blue

Lammtacus

FIGURE 1.4

Myelin-stained section of the A. Pons and. B. Medulla.

Lammtacus

FIGURE 1.4

Myelin-stained section of the A. Pons and. B. Medulla.

Lateral Corticospinal Fasciculus Cuneatus Fasciculus Gracilis Clarke's Column Posterior Commissure

Lateral Corticospinal Fasciculus Cuneatus Fasciculus Gracilis Clarke's Column Posterior Commissure

Clarke Column

FIGURE 1.5

Myelin-stained sections of the spinal cord.

FIGURE 1.5

Myelin-stained sections of the spinal cord.

TABLE 1.2.

Common Histochemical Stains

Substance

Stains

Results

Lipid*

Oil-red O

Red

Sudan III, IV

Orange-red, orange

Sudan B-Black

Blue-black

Carbohydrate

Periodic acid Schiff

Bright rose red

(PAS) with and

without diastase

Glycogen

Best carmine

Bright red

Amyloid

Congo-red

Deep pink red

Congo-red in

polarized light

Green refringence

Thioflavine S in

fluorescent light

Yellow-yellow

green

Calcium

Von Kossa

Black

Ferrous iron

Turnbull blue

Blue

Ferric iron

Prussian blue

Blue

*Frozen section

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