An unusual myopathy: speckled muscle fibers due to enlarged mitochondria.
We report a 52-year-old woman who presented with a 6-month history of proximal muscle weakness, elevated serum creatine kinase, and myopathic pattern on electromyography (EMG). Histology of the muscle shows a speckled pattern due to clustering of enlarged mitochondria. The pathology resembles that of selenium deficiency. The patient was found to have borderline low serum selenium and also low vitamin D and thyroid-stimulating hormone. The cause of this unusual myopathy is probably multifactorial. This case is important because the unusual pathological picture represents a potentially treatable myopathy. In addition, we hope that publication of the complex clinical and biochemical abnormalities of this case, in conjunction with other case reports, may facilitate future elucidation of muscle mitochondrial function and dysfunction.
Jeffree
Rosalind L
RL
Department of Neuropathology, University of Sydney and Royal Prince Alfred Hospital, Camperdown, NSW 2006, Australia.
Wills
Edward J
EJ
Harper
Clive
C
D004576:Electromyography / Q000379:methods; D005260:Female; D006801:Humans; D046529:Microscopy, Electron, Transmission / Q000379:methods; D008875:Middle Aged; D008928:Mitochondria / Q000473:pathology / Q000648:ultrastructure; D028361:Mitochondrial Diseases / Q000150:complications* / Q000473:pathology; D018485:Muscle Fibers, Skeletal / Q000473:pathology / Q000502:physiology; D009135:Muscular Diseases / Q000209:etiology* / Q000473:pathology