Giant Mitochondria in Human Muscle With Inclusions

Abstract

RECENTLY, two reports have been published on myopathies characterized primarily by abnormalities of mitochondria. In the first, Luft et al¹described a severely hypermetabolic patient with loosely coupled oxidative phosphorylation in mitochondria and, in the second, Shy et al²described pleoconial and megaconial conditions, both related to aberrent mitochondria. In Luft's patient as well as in the one with megaconial myopathy, the mitochondria in the muscle fibers were unusually large and contained striking paracrystalline inclusions. This paper reports on four patients with similar mitochondrial changes and discusses the significance of this lesion. <h3>Report of Cases</h3> In the four patients in our study, a diagnosis of either dermatomyositis, polymyositis, nephritis, or spinal muscular atrophy had been made. Each diagnosis was based on physical examination, electromyography, biopsy findings, and laboratory data. Brief summaries are given below. <h3>Case 1.—</h3> This 48-year-old man was found at 43 to have grossly elevated levels