TY - JOUR
T1 - Myofibrillar myopathy with abnormal foci of desmin positivity. I. Light and electron microscopy analysis of 10 cases
AU - Nakano, Satoshi
AU - Engel, Andrew G.
AU - Waclawik, Andrew J.
AU - Emslie-Smith, Alison M.
AU - Busis, Neil A.
PY - 1996/5
Y1 - 1996/5
N2 - A number of myopathies whose common denominator is abnormal foci of desmin positivity have been described under the rubrics of spheroid body myopathy, cytoplasmic body myopathy. Mallory body myopathy, myopathy with granulofilamentous inclusions, desmin storage myopathy, and intermediate filament myopathy. In this study we reevaluate the light microscopic and ultrastructural features of the myopathy with abnormal loci of desmin positivity. In 10 cases of the disease, ultrastructural analysis reveals 2 major types of lesions: (a) loci of myofibrillar destruction and (b) hyaline structures that appear as spheroidal bodies on electron microscopy. The loci of myofibrillar destruction consist of fiber areas containing disrupted myofilaments, Z-disk-derived bodies, dappled dense structures of Z-disk origin, and streaming Z-disks that are sometimes adjacent to lakes of dense material. The spheroid bodies are composed of compacted and degraded myofibrillar elements. Membrane-bound vacuoles harboring degenerating membranous organelles are a less frequent and probably secondary abnormality. None of the lesions in muscle comprise 8 to 10 nm intermediate filaments. The findings imply that spheroid body myopathy, cytoplasmic body myopathy. Mallory body myopathy, and myopathy with granulofilamentous inclusions are consequences of a single or closely related pathologic processes. Because the common denominator appears to be focal dissolution of the myofibrils followed by accumulation of the products of the degradative process, we propose the term myofibrillar myopathy to cover the observed spectrum of pathologic changes.
AB - A number of myopathies whose common denominator is abnormal foci of desmin positivity have been described under the rubrics of spheroid body myopathy, cytoplasmic body myopathy. Mallory body myopathy, myopathy with granulofilamentous inclusions, desmin storage myopathy, and intermediate filament myopathy. In this study we reevaluate the light microscopic and ultrastructural features of the myopathy with abnormal loci of desmin positivity. In 10 cases of the disease, ultrastructural analysis reveals 2 major types of lesions: (a) loci of myofibrillar destruction and (b) hyaline structures that appear as spheroidal bodies on electron microscopy. The loci of myofibrillar destruction consist of fiber areas containing disrupted myofilaments, Z-disk-derived bodies, dappled dense structures of Z-disk origin, and streaming Z-disks that are sometimes adjacent to lakes of dense material. The spheroid bodies are composed of compacted and degraded myofibrillar elements. Membrane-bound vacuoles harboring degenerating membranous organelles are a less frequent and probably secondary abnormality. None of the lesions in muscle comprise 8 to 10 nm intermediate filaments. The findings imply that spheroid body myopathy, cytoplasmic body myopathy. Mallory body myopathy, and myopathy with granulofilamentous inclusions are consequences of a single or closely related pathologic processes. Because the common denominator appears to be focal dissolution of the myofibrils followed by accumulation of the products of the degradative process, we propose the term myofibrillar myopathy to cover the observed spectrum of pathologic changes.
KW - Desmin
KW - Electron microscopy
KW - Myofibrils
KW - Myopathy
KW - Spheroid bodies
KW - Z disk
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U2 - 10.1097/00005072-199605000-00008
DO - 10.1097/00005072-199605000-00008
M3 - Article
C2 - 8627346
AN - SCOPUS:0029875349
SN - 0022-3069
VL - 55
SP - 549
EP - 562
JO - Journal of neuropathology and experimental neurology
JF - Journal of neuropathology and experimental neurology
IS - 5
ER -