An autopsy case of hemimegalencephaly

Dambska, M; Wisniewski, Krystyna E.; Sher, Joanna

doi:10.1016/s0387-7604(84)80012-1

Cited by 35 publications

(8 citation statements)

References 4 publications

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“…2,25,49,50 Hemimegalencephaly is considered a serious malformation, with a high mortality in infancy, unrelated to surgery. 13,30,[33][34][35]45,[51][52][53][54][55][56][57][58] At present, however, mild, moderate, and severe cases are being recognized; the mildest cases are infrequently identified.…”

Section: Classificationmentioning

confidence: 99%

“…14,23,25,26 Our histopathologic studies, however, suggest that hemimegalencephaly is more likely to be an earlier (ie, the 3rd week of gestation), genetically programmed developmental disorder related to cellular lineage and establishment of synunetry.27,28 This concept has led us to reclassify this malfon-nation. 11 Hemimegalencephaly has also been considered a primary disorder of proliferation 13,17,[11][12][13][14][15][16][17][18][19][20][21][22][23]30,31 ; if this is the case, it occurs early and possibly continues beyond the normal proliferative period. 32…”

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Hemimegalencephaly: Part 1. Genetic, Clinical, and Imaging Aspects

2002

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Hemimegalencephaly is a rare hamartomatous malformation of the brain, remarkable for its extreme asymmetry. It can be isolated or associated with several neurocutaneous syndromes; less frequently, it also involves the brain stem and cerebellum. Traditionally, hemimegalencephaly has been considered a primary neuroblast migratory disturbance. At present, genetic theories of pathogenesis and modern histopathology provide a basis for this complex malformation as a primary disturbance in cellular lineage, differentiation, and proliferation, interacting with a disturbance in gene expression of body symmetry, with earlier onset than radial neuroblast migration. From my personal experience with 10 patients with hemimegalencephaly and review of the literature, I have found the same clinical neurologic, neuroimaging, and neuropathologic features in isolated and syndromic hemimegalencephaly. Magnetic resonance imaging (MRI) reveals abnormal gyration, ventriculomegaly, colpocephaly, an "occipital sign" (displacement of the occipital lobe across the midline), and increased volume and T2 signal of white matter, in addition to the overall increased size of the involved hemisphere. Mild, moderate, and severe grades of severity can be recognized, providing a functional neurologic prognosis and therapeutic plan. Early diagnosis is crucial because despite neuroimaging and pathologic evidence, hemimegalencephaly sometimes still is unrecognized. Also, misdiagnosis of obstructive hydrocephalus or cerebral neoplasm can lead to unnecessary surgical procedures. Although hemispherectomy has a high morbidity, it is recommended early for patients with severe, intractable epilepsy. The mildest forms of hemimegalencephaly are infrequent and the least recognized.

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Section: Classificationmentioning

confidence: 99%

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confidence: 99%

Hemimegalencephaly: Part 1. Genetic, Clinical, and Imaging Aspects

2002

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“…Hemimegalencephaly is a rare, congenital abnormality consisting of diffuse, unilateral, hypertrophy of the brain. Until now, there have been relatively few neuropathological studies of this condition; they comprise only isolated (Laurence, 1964;Bignami, Palladini & Zappella, 1968;Dom & Brucher, 1969;Townsend, Nielsen & Malamud, 1975;Tjiam et al, 1978;Manz et al, 1979;Dambska, Wisniewski & Shek, 1984;King et al, 1985). We present four more cases of this condition and discuss its nosology and pathophysiology.…”

Section: Introductionmentioning

confidence: 99%

Hemimegalencephaly: A Clinicopathological Study of Four Cases

Robain

Floquet

Heldt

et al. 1988

Neuropathology Appl Neurobio

107

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“…Microscopically, HME shows a lack of normal lamination and the presence of giant neurons scattered throughout the cortex/subcortical white matter. Although the etiology of HME remains largely unknown [12], there is evidence of a neuronal migration deficit during a critical period of brain development [6,10]. Since the development and differentiation of numerous brain neurons are affected by the local synthesis and release of neurotrophins, we have investigated the expression of NGF/BDNF and their receptors in HME.…”

Section: Introductionmentioning

confidence: 99%

Nerve Growth Factor and Brain-Derived Neurotrophic Factor in Human Paediatric Hemimegalencephaly

Antonelli¹,

Chiaretti²,

Amendola³

et al. 2004

Neuropediatrics

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Paediatric hemimegalencephaly (HME) is a congenital central nervous system (CNS) disorder, characterized by monolateral cerebral hemisphere enlargement, intractable seizures starting in the post-neonatal period, and mental retardation associated with neuropathological anomalies (mainly cortical thickness and lack of lamination). Nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) are two neurotrophic factors produced in the mammalian CNS that are involved in the survival, development, and function of a variety of brain cells. In the present study, we found increased cerebral tissue levels of NGF and BDNF in 4 infants with HME; these changes appear to be also associated with abnormal NGF-receptor expression in subcortical blood vessels. Moreover, the marked reduction of cortical choline acetyltransferase immunoreactivity is strongly suggestive of a dysregulation in the NGF differentiative activity in this site that could lead to the pathogenesis of HME.

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An autopsy case of hemimegalencephaly

Cited by 35 publications

References 4 publications

Hemimegalencephaly: Part 1. Genetic, Clinical, and Imaging Aspects

Hemimegalencephaly: Part 1. Genetic, Clinical, and Imaging Aspects

Hemimegalencephaly: A Clinicopathological Study of Four Cases

Nerve Growth Factor and Brain-Derived Neurotrophic Factor in Human Paediatric Hemimegalencephaly

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