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Neuromuscular 10

Topic: Pathology

Created on Thursday, February 26 2009 by jdmiles

Last modified on Thursday, February 26 2009.


Courtesy of Dr. Mark Cohen
What does this biopsy specimen show?

 
        A) A Bear.
 
        B) Muscle from someone with really bad neuropathy
 
        C) A Meningioma
 
        D) Normal muscle
 
        E) Myopathic muscle
 

 


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This question was created on February 26, 2009 by jdmiles.
This question was last modified on February 26, 2009.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ANSWERS AND EXPLANATIONS




A) A Bear.

This answer is incorrect.


No. The image at the top of the page is muscle.
Bears look like this:

  (See References)

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B) Muscle from someone with really bad neuropathy

This answer is incorrect.


The image in question (above, at the top of this page) is an H&E-stained biopsy of skeletal muscle from a person with centronuclear myopathy.

The image below shows an NADH-stained muscle biopsy from someone with denervated (i.e., neuropathic) muscle. A couple of classic neuropathic changes include increased angularity of muscle fibers, formation of target fibers. both of these features can be seen in the image below, but not in the image at the top of this page, which the question asked about.

Courtesy of Dr. Mark Cohen

Please note that target fibers can be easily confused with central cores -- they are not the same thing. Use the search bar to look for "CCD" or "Core" or "Central core disease" for more specific information.   (See References)

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C) A Meningioma

This answer is incorrect.


No. This is muscle.  (See References)

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D) Normal muscle

This answer is incorrect.


The image in question (above, at the top of this page) is an H&E-stained biopsy of skeletal muscle from a person with centronuclear myopathy.

Normal muscle would not be as rounded. The fibers in normal muscle would not have as much variation in size. A sample of normal muscle is shown below:

Courtesy of Dr. Mark Cohen

  (See References)

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E) Myopathic muscle

This answer is correct.


This is an H&E-stained biopsy of skeletal muscle from a person with centronuclear myopathy.

Classic myopathic changes are seen in this image: fiber size variability, rounding of muscle fibers, and centrally located nuclei.

Fiber Type Variability
The muscle fibers are varied in size - some are quite large, some are very small. In a biopsy of normal muscle, most muscle fibers would appear to be about the same size.

Rounded Fibers
Normally, muscle fibers cut in cross-section have a polygonal appearance. In neuropathy, the angulation of the fibers becomes exaggerated. In myopathy, the fibers become more rounded.

Centrally Located Nuclei
Muscle fibers are polynuclear syncytia rather than cells with a single nucleus. The nuclei in normal muscle fibers are located on the periphery, close to the cell membrane. In myopathy, the muscle fibers get more centrally located.

For more information, check out gliageek's video presentation on "Denervation, Dystrophy, and Disorders of Energy Metabolism" (search for it in the search bar, or check out the link at the bottom of this page).  (See References)

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References:

1. Prayson, R.A., and Goldblum, J.R. (Eds.) (2005). Neuropathology. Elsevier Churchill Livingstone, Philadelphia. (ISBN:0443066582)Advertising:
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pathology
Neuromuscular 10
Question ID: 022609204
Question written by J. Douglas Miles, (C) 2006-2009, all rights reserved.
Created: 02/26/2009
Modified: 02/26/2009
Estimated Permutations: 120

User Comments About This Question:

1 user entries
 

jdmiles
pathology Myopathy vs Denervation Feb 26, 2009 @ 20:36

Here's the url for gliageek's video on "Denervation, Dystrophy, and Disorders of Energy Metabolism":

http://frontalcortex.com/?page=oll&qid=1088&topic=24



 
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