Ulegyria refers to a shrunken and flattened cortex, usually due to global hypoxic ischaemic injury in term infants, centring on the deepest portion of gyri, usually in the parasagittal region. Here, perfusion is most tenuous and, therefore, most susceptible to ischaemic damage ¹.

Clinical presentation

It is one of the leading causes of posterior cortex epilepsy ². Depending on the degree of damage, individuals may also have cerebral palsy and developmental delay ⁴.

Pathology

The pattern of cerebral damage that results from perinatal/neonatal hypoxic-ischaemia depends on both gestational age (preterm or term) as well as the degree of insult (acute profound versus sustained partial asphyxia). Ulegyria is usually the result of sustained incomplete hypoxia in term babies ⁴.

Damage occurs in a borderzone distribution between the middle cerebral artery and posterior cerebral artery territories. A region of ulegyria is characterised by mushroom-shaped morphology of gyri. The crest of the gyri is relatively spared, whereas the cortex and subcortical white matter within the depth of the sulcus are atrophied ^2-4.

Radiographic features

MRI

Ulegyria is characterised by an ill-defined region typically within the poterior temporal, parietal, occipital region with volume loss and increased T2/FLAIR signal of the subcortical white matter ^3,4. The overlying gyri are atrophic with relative sparing of the crest leading to so-called mushroom morphology ^2-4.

History and etymology

The term ulegyria is derived from the Greek ule meaning "scar" and was coined by Bresler in 1899 ⁴. In this publication, he also likened the appearance to mushrooms ³.