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HIV: Immune Reconstitution Inflammatory Syndrome (IRIS)

General Perimysial pathology Endomysial pathology Muscle fibers & Immune cells Similar pathology: GVH

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H & E stain

Perimysium: Wide; Fragmented
Endomysium: Increased; Histiocytic cells
Muscle fibers: Varied size; Small

H & E stain

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Gomori trichrome stain

Perimysium: Wide; Fragmented
Endomysium: Increased; Histiocytic cells
Muscle fibers: Varied sizes; Small fibers round

VvG stain

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IRIS: Perimysial Pathology

Gomori trichrome stain

Esterase stain

Perimysium & Endomysium: Many histiocytic cells

Acid phosphatase stain

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Esterase stain

Perimysium & Endomysium: Many histiocytic cells

Acid phosphatase stain

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IRIS: Endomysial Histiocytic Cells

Esterase stain

Histiocytes: Large, irregular shaped cells are scattered in the endomysium Endomysial connective tissue: Increased between muscle fibers Esterase stain

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Histiocytes: Stain with acid phosphatase Acid phosphatase stain

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IRIS: Muscle fiber pathology & Histiocytic cellularity

H & E stain Muscle fibers: Atrophy; Internal nuclei Inflammation: Large cells in endomysium

H & E stain

H & E stain

Endomysial vessels: Large size; Thick walls; Large endothelial cells (Arrow) H & E stain

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Gomori trichrome stain Endomysial connective tissue: Mildly increased Muscle fibers: Varied size; Cytoplasmic bodies in some fibers

Gomori trichrome stain

Cytoplasmic bodies: Many, clustered, in one muscle fiber Gomori trichrome stain

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Endomysial capillaries: Large size; Thick wall; Enlarged endothelial cells Gomori trichrome stain

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VvG stain Muscle fibers: Varied sizes Inflammatory cells: Scattered in endomysium between muscle fibers

VvG stain

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Inflammatory cells: Scattered in endomysium between muscle fibers

Congo red stain

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Immature muscle fibers: Intermediate stained (2C) ATPase pH 4.3 stain

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Immature muscle fibers: Coarse internal architecture NADH stain

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Immature Muscle Fibers: Some small fibers stain for alkaline phosphatase Alkaline phosphatase stain

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Mitochondrial proliferation: Increased SDH staining in scattered muscle fibers Succinate Dehydrogenase (SDH) stain

COX negative muscle fibers: Some fibers have reduced, or absent, staining for cytochrome oxidase (COX) Cytochrome oxidase (COX) stain

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12/7/2017