Sarcoidosis: Muscle
Sarcoidosis: Early images of nodular sarcoid involving muscle (Sundelin 1925)
![](../pics/biopsy/inflammation/sarcoid/sundelinmuscgran1925sm2.jpg)
Sundelin 1
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![](../pics/biopsy/inflammation/sarcoid/muscgransundelin1925hpsm2.jpg)
Sundelin
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Resolving Granuloma
Sarcoidosis: Patterns of sarcoid involving muscle
Immune myopathies with Perimysial connective tissue pathology (IMPP) & Granulomas
![](../pics/biopsy/inflammation/sarcoid/sarcibmgranperimyshelp.jpg)
H&E stain
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Granuloma in Perimysium
Muscle fibers: Scattered small fibers in areas remote from granuloma
Perimysium: Fragmented structure
Myopathy: Multiple focal regions with
Small muscle Fibers
Increased endomysial connective tissue
Inflammation: Small cluster of cells, possibly replacing a muscle fiber
![](../pics/biopsy/inflammation/sarcoid/sarcoidhevlp.jpg)
H&E stain
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Histiocytic inflammation
Clusters of histiocytes
In granulomas
Associated with necrotic muscle fibers
Scattered histiocytes: in perimysial connective tissue
![](../pics/biopsy/inflammation/sarcoid/sarcibmacplp.jpg)
Acid phosphatase stain
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![](../pics/biopsy/inflammation/sarcoid/sarcoid2crvlp.jpg)
Congo red stain
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Chronic Sarcoid myopathy
Perimysium & Endomysium: Replaced by Fat
Granulomas with giant cells in endomysium or perimysium
![](../pics/biopsy/inflammation/sarcoid/sarcoid2crvlp2gran.jpg)
Congo red stain
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![](../pics/biopsy/inflammation/sarcoid/sarcibmgranperimyshehp.jpg)
H&E stain
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Granuloma in Perimysium
![](../pics/biopsy/inflammation/sarcoid/sarcibmgran.jpg)
H&E stain
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Granulomas in Endomysium
Large cells & multinucleated cells in central regions
Smaller cells (Lymphocytes) in peripheral regions
Small muscle fibers often neighbor granuloma in some areas
![](../pics/biopsy/inflammation/sarcoid/sarcoidgrancr.jpg)
Congo red stain
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![](../pics/biopsy/inflammation/sarcoid/granvvgmp.jpg)
VvG stain
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Granuloma
Small muscle fibers in periphery of granuloma
![](../pics/biopsy/inflammation/sarcoid/sarcoid2acpmpgran.jpg)
Acid phosphatase stain
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Granuloma
Acid phosphatase (Above) stains
Around nuclei of individual histiocytes
Diffusely in Cytoplasm of giant cell
Esterase (Below) stains
Cells within granuloma in confluent pattern
![](../pics/biopsy/inflammation/sarcoid/sarcoid2estmpgran.jpg)
Esterase stain
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Granuloma
Cells in granuloma have abundant mitochondria
![](../pics/biopsy/inflammation/sarcoid/sarcgransdh.jpg)
SDH stain
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Granuloma
Cells in granuloma stain strongly for histiocyte marker CD68
Activated histiocytes (CD68+) are also scattered in endomysium, possibly near capillaries
![](../pics/biopsy/inflammation/sarcoid/sarcoidcd68.jpg)
CD68 stain
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Sarcoid: Small Granulomas
![](../pics/biopsy/inflammation/sarcoid/granmfhehp.jpg)
H&E stain
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Granulomas (Early)
Histiocytes replace muscle fibers & remain in place
![](../pics/biopsy/inflammation/sarcoid/sarcoidgransmcr.jpg)
Congo red stain
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![](../pics/biopsy/inflammation/sarcoid/gransmvvgmp.jpg)
VvG stain
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Sarcoidosis, Chronic: Muscle fiber pathology
![](../pics/biopsy/inflammation/sarcoid/sarcoidvvgmp3.jpg)
VvG stain
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Sarcoidosis: Muscle fiber pathology
Immune cells surround muscle fibers (Above)
Muscle fiber damage: Muscle fibers focally invade & progressively replace muscle fibers (Below; Arrow)
![](../pics/biopsy/inflammation/sarcoid/sarcoidgtmp2ar.jpg)
Gomori trichrome stain
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![](../pics/biopsy/inflammation/sarcoid/sarcfocinvhehp.jpg)
H&E stain
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Sarcoidosis: Muscle fiber pathology
Muscle fiber damage: Muscle fibers focally invade & replace muscle fibers
![](../pics/biopsy/inflammation/sarcoid/sarcoidhehp1focinv.jpg)
H&E stain
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Many Cells replacing muscle fibers are histiocytes (CD68+)
![](../pics/biopsy/inflammation/sarcoid/sarcoidcd68invfib.jpg)
CD68 stain
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Sarcoidosis: Muscle fiber pathology
Muscle fiber damage: Fragments of muscle fibers (Arrow) remain in some areas of a granuloma
![](../pics/biopsy/inflammation/sarcoid/sarcoidhehpfocinvar.jpg)
H&E stain
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Sarcoidosis: Resolving granulomas
![](../pics/biopsy/inflammation/sarcoid/sarcoidhelp2ar.jpg)
H&E stain
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Granulomas, Resolving
Granulomas may resolve leaving focal regions (Arrow) with
Increased, or damaged, connective tissue
Scattered
Cells, Some
multinucleated
Small muscle fibers
![](../pics/biopsy/inflammation/sarcoid/sarcoidhempfocfib.jpg)
H&E stain
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![](../pics/biopsy/inflammation/sarcoid/sarcoidcrmp2.jpg)
Congo red stain
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Resolved Granulomas with focal regions of
Cellular connective tissue
Small muscle fibers
![](../pics/biopsy/inflammation/sarcoid/sarcoidvvghp.jpg)
VvG stain
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![](../pics/biopsy/inflammation/sarcoid/sarcperimyshehp.jpg)
H&E stain
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![](../pics/biopsy/inflammation/sarcoid/sarcoidhegchp2.jpg)
H&E stain
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Multinucleated, Large cells: In regions of resolved granulomas
![](../pics/biopsy/inflammation/sarcoid/sarcoidhegchp.jpg)
H&E stain
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![](../pics/biopsy/inflammation/sarcoid/sarcoidvvglp.jpg)
VvG stain
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Perimysial Pathology: Perimysial connective tissue
Structure: Fragmented
Contents: Scattered histiocytes
![](../pics/biopsy/inflammation/sarcoid/sarcoidvvglp2.jpg)
VvG stain
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![](../pics/biopsy/inflammation/sarcoid/sarcoidhemp8.jpg)
H&E stain
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Perimysial Pathology: Perimysial connective tissue
Structure: Fragmented
Contents: Scattered histiocytes
![](../pics/biopsy/inflammation/sarcoid/sarcoidhehp4perimys.jpg)
H&E stain
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![](../pics/biopsy/inflammation/sarcoid/sarcibmacpmp.jpg)
Acid phosphatase stain
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Perimysial Connective Tissue
Contains scattered histiocytes (Acid phosphatase + (Red)) in areas with normal & fragmented structure
![](../pics/biopsy/inflammation/sarcoid/sarcoidperimysacp.jpg)
Acid phosphatase stain
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![](../pics/biopsy/inflammation/sarcoid/sarcesterase.jpg)
Esterase stain
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Perimysial Connective Tissue
Contains scattered histiocytes (Esterase + (Red)) in areas with normal & fragmented structure
![](../pics/biopsy/inflammation/sarcoid/sarcesterasehp.jpg)
Esterase stain
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Perimysial Connective Tissue
Regions in some patients have abnormal alkaline phosphatase staining
![](../pics/biopsy/inflammation/sarcoid/sarcibmalp.jpg)
Alkaline phosphatase stain
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Sarcoid muscle: Immune features
C5b-9 deposition: Endomysial & Perimysial connective tissue
![](../pics/biopsy/inflammation/sarcoid/sarcc5b9.jpg)
C5b-9 stain
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MHC Class I upregulation by muscle fibers
![](../pics/biopsy/inflammation/sarcoid/sarcibmmhc1lp.jpg)
MHC Class I stain
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![](../pics/biopsy/inflammation/sarcoid/sarcmhc1.jpg)
MHC Class I stain
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12/16/2021