Amyloid myopathy: Characteristic features of a still underdiagnosed disease

Authors

  • John E. Chapin MD,

    Corresponding author
    1. Department of Neurology, MSC 10 5620, 1 University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131-0001, USA
    2. Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
    • Department of Neurology, MSC 10 5620, 1 University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131-0001, USA
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  • Mario Kornfeld MD,

    1. Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
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  • Alexis Harris MD

    1. Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
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Abstract

A 62-year-old man with progressive proximal weakness underwent extensive evaluation including muscle biopsy without a clear diagnosis being established. A repeat muscle biopsy including Congo red–stained sections revealed infiltration of blood-vessel walls and endomysium with amyloid protein, as well as an unusual pattern of pathologic changes to muscle fibers. From a review of 79 cases of amyloid myopathy reported in the English-language literature, the characteristic features of this disorder are described. Congo red–stained sections of muscle biopsy viewed under fluorescent or polarized optics, and serum or urine protein immunoelectrophoresis, play an important role in the evaluation of myopathy. Amyloid myopathy should be a consideration in adults with progressive neuromuscular weakness of uncertain cause. Muscle Nerve, 2004

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