Posterior quadrantic dysplasia or hemi-hemimegalencephaly

Abstract

Widespread cortical dysplasia is more frequent in the posterior quadrant. In our series, posterior quadrantic dysplasia represents either hemi-hemimegalencephaly or multilobar cortical dysplasia. Individuals with posterior quadrantic dysplasia share a spectrum of clinical features. The intractable epilepsy in these patients may be alleviated by a large quadrantic temporoparieto-occipital resection.

Hemispherotomy and other disconnective techniques

“…Four patients who underwent posterior functional hemispherectomy were described by D'Agostino et al 14 The outcome was not as good in this group, with Engel Class I attained in only one case.…”

Epilepsy Related to Developmental Tumors and Malformations of Cortical Development

“…HME can occur as an isolated malformation or associated with several syndromes [230,231,233,234]. A large spectrum of central nervous system structural abnormalities have been reported, including cases variously defined as "hemimegalencephaly", "focal megalencephaly" "lobar dysplasia", or "localized megalencephaly", in which the abnormalities are detected only over a partial area of one hemisphere [235][236][237]. In these cases, the detection of associated extracerebral abnormalities (e.g., ipsilateral olfactory nerve enlargement, cerebral vascular dilations, cerebellar enlargement with abnormal architecture of the cerebellar folia) has been suggested to provide help in differentiating localized megalencephaly from multilobar cortical dysplasia [237].…”

Aberrant Midsagittal Fiber Tracts in Patients with Hemimegalencephaly

“…[1][2][3][4][5][6] These morphologic, histologic, and MR imaging findings have previously been described. [7][8][9] However, to our knowledge, no reports have focused on abnormal midsagittal structures.…”