Pachygyria

Newborn with
hydrocephalus on prenatal ultrasound. Axial T1 (left) and axial T2 (right) MRI without contrast of the brain shows a decreased number of gyri and sulci resulting in a nearly smooth brain. There is ventriculomegaly. Overall the brain has an hourglass or figure of 8 appearance. The diagnosis was lissencephaly type I classic.
pediatricimaging.org • CC-by-nc-sa 4.0
Galloway-Mowat
syndrome in Taiwan: OSGEP mutation and unique clinical phenotype. Images of fetal ultrafast MRI. a Patient III-1 at 34 weeks of gestation shows pachygyria, especially in the bilateral frontal lobes, and poor myelination of the white matter (b) Patient III-2 at 32 weeks of gestation shows hypomelination with T2 hyperintensity in bilateral cerebral white matter, particularly both temporal lobes (arrows), and prominence of retrocerebellar cisterns due to cerebellar atrophy (arrowheads)
ojrd.biomedcentral.com • CC-by-4.0
Galloway-Mowat
syndrome in Taiwan: OSGEP mutation and unique clinical phenotype. Brain images of the patients. a Non-contrast enhanced axial carnial CT scan of patient II at 2 days of age showed pachygyria involving bilateral cerebral hemispheres. b Axial sections of MRI of patient III-1 at 9 weeks of age showed gyral abnormalities, frontal pachygyria, and deficient myelination. c MRI of patient III-2 at 6 days of age showed pachygyria and hypomyelination with T2 high signal intensity of white matter in bilateral frontal and temporal lobes. d Non-contrast enhanced axial carnial CT scan of patient V at 1 month of age showed pachygyria involving bilateral cerebral hemispheres
ojrd.biomedcentral.com • CC-by-4.0
Lissencephaly
type I - subcortical band heterotopia spectrum • Type I lissencephaly - Ganzer Fall bei Radiopaedia
Gaillard, F. Type I lissencephaly. Case study, Radiopaedia.org. (accessed on 08 Nov 2022) https://doi.org/10.53347/rID-10595 • CC by-nc-sa 3.0 (modified)
Lissencephaly
type I - subcortical band heterotopia spectrum • Lissencephaly type I - Ganzer Fall bei Radiopaedia
Gaillard, F. Lissencephaly type I. Case study, Radiopaedia.org. (accessed on 08 Nov 2022) https://doi.org/10.53347/rID-6620 • CC by-nc-sa 3.0 (modified)
Management of
general anesthesia in a child with Miller–Dieker syndrome: a case report. Head computed tomography (CT). Head CT showing type I lissencephaly with midline calcification
jaclinicalreports.springeropen.com • CC-by-4.0
Radiopaedia • CC-by-nc-sa 3.0 • de

The lissencephaly-pachygyria spectrum is a useful way to describe the spectrum of diseases that cause relative smoothness of the brain surface and includes:

  • agyria: no gyri
  • pachygyria: broad gyri
  • lissencephaly: smooth brain surface

It is a basket term for a number of congenital cortical malformations characterized by absent or minimal sulcation.

Lissencephaly-pachygyria can be further divided into types I (classic) and type II (cobblestone). They differ in clinical presentation, underlying genetic abnormalities, as well as microscopic and macroscopic (including imaging) appearances . They themselves represent a heterogeneous group of disorders. This article highlights a few generalities and outlines the differences between the two types, which are otherwise discussed separately:

Clinical presentation

Type I (classic) lissencephaly typically presents with marked hypotonia and paucity of movement.

Type II lissencephaly is associated with muscular dystrophy-like syndromes and includes Walker-Warburg syndrome, Fukuyama syndrome, and muscle-eye-brain (MEB) disease .

Radiographic features

Although lissencephaly can be identified on all cross-sectional modalities (antenatal and neonatal ultrasound, CT and MRI), MRI is the modality of choice to fully characterize the abnormalities.

MRI 

Type I and type II lissencephaly demonstrate vaguely similar appearances (thus the common term lissencephaly) but different macroscopic and imaging appearances are visible.

Type I (classic) lissencephaly can appear as the classic hourglass or figure-8 appearance or with a few poorly formed gyri (pachygyria) and a smooth outer surface. It is usually associated with band heterotopia.

Type II lissencephaly, on the other hand, has a microlobulated surface referred to as a cobblestone complex. Band heterotopia is not evident and the cortex is thinner than in type I.

History and etymology

Lissencephaly is derived from the Greek word λισσος (lissos), meaning smooth .

See also

Siehe auch:
und weiter:
Assoziationen und Differentialdiagnosen zu Lissenzephalie:
Walker-Warburg-Syndrom
 
jmhg.springeropen.com • CC-by-4.0
Lissenzephalie
Typ 1
pediatricimaging.org • CC-by-nc-sa 4.0
Miller-Dieker
Syndrom
jaclinicalreports.springeropen.com • CC-by-4.0