[Muscle and brain biopsy in a case of mitochondrial encephalomyopathy. Demonstration of a mitochondrial vasculopathy].

The authors report the case of a 14-year-old boy who presented with shunted growth and low weight gain, asthenia with fatiguability on effort, clinical signs of myopathy, ataxia, epilepsy, deafness, loss of visual acuity and reduced intellectual capacities. Muscle biopsy revealed numerous ragged-red fibres and mitochondrial anomalies at ultrastructural examination. Cerebral biopsy showed spongiform changes. Both muscular and cerebral biopsies showed vascular lesions: swollen endothelial cells. Mitochondria increased in number with concentric whorls of cristae were observed in pericytes and smooth muscle cells. This mitochondrial vasculopathy could explain the neurological symptoms.