[Kearns-Sayre syndrome: pediatric neuroradiologic findings in computed tomography and magnetic resonance imaging].

Clinical presentation of mitochondrial disorders is heterogeneous because the affected organs are those depending on a high rate of aerobic metabolism. They can appear at any age and evolution is progressive. Signs that guide diagnostic suspicion, especially in the pediatric age group, are heterogeneous clinical presentation and multisystem involvement. Within the spectrum of diseases caused by mitochondrial myopathy, there are clearly defined syndromes such as Kearns-Sayre syndrome. Muscle biopsy shows ragged red fibers and approximately 80 % of patients present sporadic deletions in mitochondrial DNA. Imaging studies reveal areas of hypointensity in basal ganglia and midbrain that are not visible after administration of contrast enhancement in computed tomography, and symmetric T2 hyperintensity lesions in these areas in magnetic resonance imaging. We present a patient with Kearns-Sayre syndrome, in whom radiological alterations were helpful in reaching the diagnosis.