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Washington University Experience | MUSCLE | Atrophy, muscle cell, NOS | 13A1-Case-13-Vas-Lat-Muscle_008.jpg

Case 13 History ---- The patient is a 41-year-old woman with a history of mitochondrial disease with high serum lactic acid. Biopsy showed abnormal variation in muscle fiber sizes with some fiber hypertrophy. Chronic denervation was manifest by minor fiber type grouping. Ultrastructural analysis shows abnormal mitochondria in size, shape, number and subsarcolemmal distribution and association with lipid droplets. However, the giant mitochondria, ring shapes, large accumulations and inclusions (e.g., “parking lot” inclusions) typically seen in mitochondrial encephalomyopathy were not encountered. ---- 13A1,2 Atrophic fibers show cytoplasmic pallor, loss of the myofibrillar apparatus, and multinuclear knots.

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