Pachygyria, Polymicrogyria | Walif Chbeir

                                                                                         Walif Chbeir Radiology Notes

                                                                                            Edited on January, 09, 2017    


Pachygyria, Polymicrogyria


Pachygyria: Broad, flattened gyri; thickened cortex

Polymicrogyria: Many small gyri

Pachygyria and polygyria often occur together

* MR Findings

Flatter, broader shape to gyri than normal, thick cortex

Initially irregular cortex progressing to too many infoldings of cerebral surface.

Fine sawtooth or zigzag appearance to cortex

Lissencephaly Type 1
   “Smooth” brain.  Absence or diminished number of cortical sulci throughout cerebral hemispheres with thick cortex.

     Hourglass or figure 8 shape of cerebral hemispheres.

     Normocephalic to microcephalic.
     Spectral continuum with polymicrogyria-pachygyria.

* Most often seen in association with other brain abnormalities

Mild ventriculomegaly
Nodular ventricular walls suggest heterotopic gray matter.

Agenesis of corpus callosum Or other brain malformation associated with absent cavum septi pellucidi.

Intracranial cyst

Cerebellar hypoplasia

* Differential Diagnosis

Cobblestone lissencephaly = Type 2 Lissencephaly.  Fine nodular brain surface,Pebbly” surface of brain,  Disorganized unlayered cortex, many neurons move too far into subpial space → cobblestone complex.
  Associated ocular findings in Walker-Warburg syndrome, cerebellar abnormalities, congenital muscular dystrophy.

* Etiology
Metabolic disorders.
Infection: CMV, toxoplasmosis, parvovirus
Ischemia, teratogens
Genetics: gene mutations.

* PolyMicroGyria is probably common endpoint of variety of aberrations of cortical development.

* Courtesy of:

1- Anne Kennedy, MD, in Statdx: Obstetrics > Diagnosis > Brain > Cortical Developmental Anomalies :  Pachygyria, Polymicrogyria.

2- Blaise V. Jones, MD, in Statdx: Brain > Diagnosis > Pathology-based Diagnoses > Congenital Malformations > Malformations of Cortical Development : Lissencephaly.