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moderate reduction in the number of sulci of the cerebrum, sometimes with increase in the brain substance, resulting in excessive size of the gyri.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.


Condition in which the convolutions of the cerebral cortex are abnormally large; there are fewer sulci than normal and in some cases the amount of brain substance is somewhat increased.
Synonym(s): macrogyria
[pachy- + G. gyros, circle]
Farlex Partner Medical Dictionary © Farlex 2012


Condition in which the convolutions of the cerebral cortex are abnormally large; there are fewer sulci than normal and the amount of brain substance may be increased.
[pachy- + G. gyros, circle]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
References in periodicals archive ?
C, Pachygyria, ventriculomegaly, pseudocysts (asterisks), and calcifications (arrow) in occipital lobes.
Grade II lissencephaly is characterized by diffuse agyria with few shallow sulci over the frontal, temporal or occipital lobes and diffuse pachygyria (DOBYNS &TRUWIT, 1995).
Pachygyria which is a nonspecific finding in patients with MCPH1 mutation was also present in our patient.
In that study; among mild ventricular enlargement group 7 of 39 and among moderate ventricular enlargement group all five children had other significant accompanying abnormalities.13 Within our study group half of the cases had abnormality like cerebral atrophy, porencephalic cyst, arachnoid cyst or pachygyria (Table-I).
([dagger]) Brain abnormalities or microcephaly (congenital microcephaly [head circumference <3rd percentile for gestational age and sex], intracranial calcifications, cerebral atrophy, abnormal cortical gyral patterns [e.g., polymicrogyria, lissencephaly, pachygyria, schizencephaly, gray matter heterotopia], corpus callosum abnormalities, cerebellar abnormalities, porencephaly, hydranencephaly, ventriculomegaly/hydrocephaly [excluding "mild" ventriculomegaly without other brain abnormalities], fetal brain disruption sequence [collapsed skull, overlapping sutures, prominent occipital bone, scalp rugae], other major brain abnormalities).
Diffuse cortical malformations: agyria, pachygyria, polymicrogyria, microcephaly, megalencephaly, microdysgenesis.
Categories of Malformations Associated With Congenital Zika Syndrome Category Examples Neurologic * Microcephaly * Hydrocephalus * Micrencephaly * Lissencephaly * Polymicrogyria * Pachygyria * Agyria * Holoprosencephaly * Ventriculomegaly * Corpus callosum abnormalities * Intracerebral calcifications * Destructive brain lesions Ocular * Chorioretinal atrophy * Optic nerve abnormalities * Maculopathies * Vascular abnormalities Musculoskeletal * Arthrogryposis * Craniofacial abnormalities (craniosynostosis) * Clubfoot * Acetabular dysplasia Genitourinary * Cryptorchidism * Hypospadias Other * Intrauterine growth restriction * Anasarca * Pulmonary hypoplasia * Single umbilical artery
Sixty-nine percent showed evidence of malformations of cortical development, including lissencephaly (relative smoothness of the brain surface) associated with pachygyria (poorly formed, broad cortical folds), agyria (no cortical folds), or both (Figure 2, panel B).
Lissencephaly is a developmental defect characterised by a smooth cerebral surface lacking gyri and sulci (agyria) and a thickened cortex (pachygyria) due to the abnormal distribution of neuronal cell bodies (De LAHUNTA & GLASS, 2009).
Pachygyria and corpus callosum agenesis were the most common anomalies seen in four children each.
Two-year-old Kohen Mallon has pachygyria - a condition resulting from abnormal brain and nervous system development.
(19,59) Ultrasound and/or autopsy may reveal widespread brain calcifications (periventricular, cerebral parenchyma, thalami, and basal ganglia), cortical thinning with ventricular dilation, simplified gyral patterns (eg, lissencephaly, pachygyria, agyria), and cerebellar hypoplasia.