NQ-061
Answer:
(A)
Periodic acid Schiff histochemistry
Diagnosis:
McArdle disease (Glycogenosis type V)
Pathology of this case:
This
magenta color is characteristic for PAS stain. The dark purple depositions
(arrow) are positive. This image was taken from a case of McArdle disease. There
is excess glycogen storage in this type of glycogenosis and glycogen is strongly
positive for PAS. Normal glycogen can be digested with diastase and therefore
these depositions will disappear upon diastase pre-treatment (digesting out the
glycogen) before PAS stain is performed.
The periodic
acid oxidizes the 1-2 glycol group including vicinal diols or an equivalent
amino or alkylaminao group to an aldehyde group. The aldehyde can further react
with amine group of Schiff reagent to give the signature magenta color.
[PAS stain information on online]
[PAS stain information online]
Succinate dehydrogenase:
This mitochondrial enzyme is coded by nuclear DNA. Mitochondria are stained
dark blue.
[Click here to see an image]
Modified Gomori’s trichrome:
This
stain is used in muscle biopsy to pick up ragged red fiber in mitochondrial
myopathy, inclusion bodies in inclusion body myopathy, and other
abnormalities such as nemaline body myopathy.
[Click here
to see an image]
Esterase:
This stain in biopsy can be used to pick up infiltrating infiltrates as well
as atrophic fibers in neurogenic atrophy/changes due to denervation among
others.
[Click here to see
an image]
Oil red O:
This stain can be used to demonstrate the accumulation of neutral fat
similar to Sudan black.
[Click here to see an image]