Unusual Phenotype and Disease Trajectory in Kearns–Sayre Syndrome

Figure 2

(a–c) Neuropathology of muscle biopsy (left vastus lateralis muscle) presents myopathic changes with single COX-negative fibers (a) COX/SDH double-labeling, mildly increased PAS-positivity in few fibers (b) arrow, muscle fiber splitting, and ragged-red fibers (c) Gomori-trichrome stain, asterisk. (d and e) Electron microscopy images illustrate increased numbers of fat vacuoles (d and e, arrow heads) between densly packed subsarcolemmal mitochondria (d) plus. Some mitochondria show single dark bodies in higher magnification (e) arrow.