An unusual myopathy: Speckled muscle fibers due to enlarged mitochondria

Abstract

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.

The WOMED model of benign thyroid disease: Acquired magnesium deficiency due to physical and psychological stressors relates to dysfunction of oxidative phosphorylation

“…Hypothyroid myopathy has been found to show absence of mitochondria [236] . A case of myopathy in relation with selenium deficiency was described as being associated with muscle weakness [237] . Recently interest on mitochondrial function has been described in the field of infertility [238] .…”