Megalencephaly

Megalencephaly is primarily a proliferative disorder of embryonic origin, macroscopically defined as enlargement of part of or all of the cerebral hemispheres. It could be bilateral or unilateral. Often polymicrogyria or agyria is found in association. 

This slightly differs from the term macrocephaly which means an increase in size of the cranial vault.

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It may be apparent as abnormal head circumference measurements, especially noted in the first four months of life.  

Mental retardation, seizures and other neurological abnormalities have been reported. It is important to emphasise that there is not a classical pattern of symptoms 2

Megalencephaly is a complex abnormal cell proliferation process representing excessive amount of normal brain constituents, cellular proliferation, inadequate physiologic apoptosis, and/or storage of metabolites 1

Associations

It can occur in a variety of syndromes including

MRI

MRI may show a thickened cortex with ipsilateral ventricular dilatation on the side of the megalencephaly and this feature allows differential diagnosis between congenital hemimegalencephaly from other causes, such as a lesion obstructing the foramen of Monro.

Malformations of the central nervous system
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rID: 1654
Tags: cases, refs
Synonyms or Alternate Spellings:

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