title: Mitochondrial encephalomyopathy of mixed MELAS type.
abstract: A 27-year-old man with slowly progressing symptoms of pigmentary retinal degeneration, cerebellar, pyramidal and extrapyramidal syndrome and atrophy of lower limb muscles, was admitted to the Department of Neurology. During the final stage of disease, generalized, tonic and clonic seizures, absence and myoclonic epilepsy as well as Jackson's motor seizures were observed. A computed tomographic (CT) scan showed a considerable atrophy of cerebellum and pons. A magnetic resonance imaging (MRI) revealed diffuse cortical and subcortical atrophy, especially in structures of posterior intracranial fossa and bilateral foci of increased signal intensity in cerebral cortex and subcortical gray structures. A morphological study of a biceps specimen revealed the presence of so called ragged-red fibers characterized by abnormal mitochondria with paracrystalline inclusions. A considerable atrophy of the central nervous system, especially of cerebral and cerebellar cortex was revealed by a macroscopic study of the brain. Numerous focal and so called pseudolaminar cortical necroses in the brain, regardless of vascular supply, with characteristic proliferation of capillary vessels were predominating in a microscopic study. The clinical data and especially histopathological features count for the diagnosis of mitochondrial encephalomyopathy of MELAS type. The presence of additional features such as pigmentary retinal degeneration, characteristic of Kearns-Sayre syndrome and myoclonic seizures typical of MERRF syndrome allows the classification of this case as mixed MELAS syndrome.
authors.affiliation: Department of Neuropathology, Institute of Psychiatry and Neurology, Warszawa.
authors.forename: E
authors.initials: E
authors.lastname: Bertrand
authors.forename: A
authors.initials: A
authors.lastname: Fidziańska
authors.forename: B
authors.initials: B
authors.lastname: Schmidt-Sidor
authors.forename: T
authors.initials: T
authors.lastname: Mendel
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology*; D017809:Fatal Outcome; D006801:Humans; D017241:MELAS Syndrome / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008928:Mitochondria / Q000648:ultrastructure; D018482:Muscle, Skeletal / Q000473:pathology*