Ulegyria is a distinctive but under-recognised form of cortical scarring that follows perinatal hypoxic-ischemic injury in the term brain. Because the depths of the sulci lie in the arterial border zones and are perfused from the pial surface inward, ischemia preferentially injures the sulcal base while sparing the gyral crown, producing atrophic convolutions with a characteristic mushroom shape. We report a 7-year-old boy, born at term with a history of failure to cry at birth and neonatal intensive care admission, who presented with global developmental delay, intellectual disability and epilepsy. Magnetic resonance imaging of the brain demonstrated brachycephaly with a simplified frontal gyral pattern, symmetrical signal hyperintensity in the perirolandic and periventricular white matter of the frontal, temporal and occipital lobes, and volume loss with atrophic, mushroom-shaped gyri in the posterior temporal, parietal and occipital watershed regions that spared the gyral crests, the hallmark of ulegyria. Secondary changes of a thinned corpus callosum and ex vacuo dilatation of the lateral ventricles were present, while the deep grey nuclei, cerebellum and brainstem were preserved. The constellation indicated chronic sequelae of term perinatal hypoxic-ischemic injury of the partial, prolonged watershed type. Recognising ulegyria allowed the injury to be confidently ascribed to the perinatal period rather than to a later insult, and explained the child’s epilepsy and developmental impairment. Familiarity with this pattern guides counselling, supports the timing of injury, and informs management of the frequently drug-resistant epilepsy.

Keywords:Ulegyria; Mushroom Gyri; Hypoxic-Ischemic Encephalopathy; Watershed Injury; Epilepsy.