---

MTTL1 Encephalomyopathy (A3251G heteroplasmic mutation) ¹

---

H&E stain

Scattered muscle fibers with: Necrosis or Irregular structure

Congo red stain

---

Muscle fibers: Lipid storage with round, clear droplets

H&E stain

---

H&E stain

Muscle fiber necrosis
  Anatomic Pattern: Scattered
  Stages: Varied

H&E stain

H&E stain

Muscle fiber necrosis
  Anatomic Pattern: Scattered
  Stages: Varied

H&E stain

---

Gomori trichrome stain

Mitochondrial Pathology: Muscle fibers
  Fibers with prominent mitochondrial proliferation are stained dark red.

Gomori trichrome stain

---

Mitochondrial Pathology: Mitochondrial oxidative enzymes in muscle fibers

Cytochrome oxidase (COX) stain

Cytochrome oxidase (COX)
  Scattered muscle fibers with increased staining
  No COX- fibers

Cytochrome oxidase (COX) stain

---

Succinate Dehydrogenase (SDH) stain

Succinate Dehydrogenase (SDH)
  Scattered muscle fibers with increased staining

Succinate Dehydrogenase (SDH) stain

Succinate Dehydrogenase (SDH) stain

Succinate Dehydrogenase (SDH)
  Scattered muscle fibers with increased staining

Succinate Dehydrogenase (SDH) stain

---

Mitochondrial Pathology: Mitochondrial oxidative enzymes in vessel walls

Succinate Dehydrogenase (SDH) stain

Succinate Dehydrogenase (SDH)
  Increased staining of wall of intermediate sized vessels in permysium

Succinate Dehydrogenase (SDH) stain

---

Cytochrome oxidase (COX)
  Increased staining of walls of intermediate sized vessels in permysium

Cytochrome oxidase (COX) stain

---

Vessels

---

Capillaries

Alkaline phosphatase stain

Alkaline phosphatase stain

Alkaline phosphatase stain

---

Perimysial Vessels

Congo red stain

Succinate Dehydrogenase (SDH) stain

Mitochondrial Pathology: Larger vessels
  Increased SDH in vessel wall & endothelial cells
  Increased lipid in vascular endothelial cells

Sudan Black stain

---

Lipid Storage in muscle fibers
  Many smaller, and some larger, muscle fibers have dark stained cytoplasm & small to moderate sized lipid droplets

Sudan stain

Sudan stain

Lipid Storage in muscle fibers
  Many smaller, and some larger, muscle fibers have dark stained cytoplasm & small to moderate sized lipid droplets
  Clear rims, possibly lipid droplets, surround parts of some muscle fibers

Sudan Black stain

---

NADH stain

Internal architecture: NADH stain
  Many small muscle fibers are dark stained

NADH stain

NADH stain

---

Neuromuscular Junctions
  Many appear large
Esterase stains cytoplasm of scattered large and small muscle fibers dark

Esterase stain

---

LC3 stain

Muscle Fiber Aggregates
  LC3 stains cytoplasmic aggregates, clustered or scatterd, in many muscle fibers

LC3 stain

LC3 stain

---

MxA stain

MTTL1 muscle
MxA stains the cytoplasm of scattered smaller muscle fibers

MxA stain

MxA stain

---

Control muscle: No MxA staining in muscle fibers

MxA stain

---

MHC Class I stain

MHC Class I stains
  Cytoplasm of scattered intermediate sized muscle fibers
  Irregular cells associated with endomysial capillaries

MHC Class I stain

---

Return to: MELAS
Return to: Neuromuscular Home Page

1. J Med Case Rep 2019;13:63

9/14/2022