Amyloid myopathy: characteristic features of a still underdiagnosed disease.
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.
Chapin
John E
JE
Department of Neurology, MSC 10 5620, 1 University of New Mexico Health Sciences Center, Albuquerque, NM 87131-0001, USA. jchapin@salud.unm.edu
Kornfeld
Mario
M
Harris
Alexis
A
D000686:Amyloidosis / Q000150:complications / Q000175:diagnosis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018908:Muscle Weakness / Q000150:complications / Q000175:diagnosis; D018482:Muscle, Skeletal / Q000737:chemistry / Q000473:pathology*; D009135:Muscular Diseases / Q000150:complications / Q000175:diagnosis*