Megaconial Pathology

MITOCHONDRIAL DISEASE: Megaconial Myopathy

Enlarged mitochondria: Causes
Congenital Myopathy: CHKB
Cardiofaciocutaneous syndrome 1: BRAF
Immune Myopathy
Selenium deficiency
Large mitochondria: Zellweger
PEX12
PEX16

H&E stain

Ongoing Myopathy, Active
Muscle Fibers: Necrosis & Regeneration, Scattered damage

Gomori trichrome stain

Muscle fibers: In varied stages of Necrosis & Regeneration

H&E stain

H&E stain

Myopathy, Chronic
Muscle fibers size: Varied
Internal nuclei: Often Single & Central

H&E stain

H&E stain

Gomori trichrome stain

Gomori trichrome stain

Muscle fibers: Stippling
Toward periphery of muscle fibers

VvG stain

H&E stain

AMPDA stain

NADH stain

Muscle Fiber Internal Architecture
Center of muscle fibers: No staining for sarcoplasmic reticulum
Periphery of muscle fibers: Punctate staining

NADH stain


Mitochondria: Large; Non-uniform distribution
COX stain	COX stain	COX stain
Mitochondria: Large; Non-uniform distribution

COX stain

SDH stain

Mitochondria
Large
Most in periphery of muscle fibers

SDH stain

SDH stain

SDH stain

ATPase pH 9.4 stain	ATPase pH 4.3 stain	Acid Phosphatase stain
Type 2 fibers are larger than type 1 Large mitochondria: More common in type 2 fibers	Scattered type 2C muscle fibers	Necrotic Muscle Fibers

Sudan stain
Lipid Droplets: Large

PAS stain
Glycogen: Increased in muscle fiber cytoplasm