BACKGROUND AND PURPOSE: Hemispheric dysplasia (HD) and hemimegalencephaly (HME) are both brain malformations with early clinical manifestation including developmental delay and intractable epilepsy. Sometimes the differentiation of these conditions is not simple. HME is an anomaly of cortical development caused by a combination of neural proliferation and cell migration dysfunction, showing lobar or hemispheric enlargement. On the other hand, HD shows no brain hypertrophy, and even brain atrophy, eventually. PATIENTS AND METHODS: To compare both conditions, we reviewed clinical, MRI, and histopathology of 23 patients with developmental delay and refractory epilepsy treated with hemispheric surgery. RESULTS: Histologically, both groups presented polymicrogyria, focal cortical dysplasia, gray matter (GM) heterotopia, pachygyria, and agyria. The white matter (WM) showed different degrees of gliosis and myelin impairment. Even though with no specificity in histopathology, the degree of lesion was more impressive on HME. The combination of WM dysmyelination and hypertrophy leads to the so called hamartomatous appearing. Although not all HME showed brain enlargement and some HD might show no size changes or atrophy, the size of affected hemisphere and the hamartomatous appearance of the WM were the more relevant signs to differentiate both conditions. CONCLUSION: Brain MRI was the best diagnostic tolls because it allowed together high contrast resolution, whole brain coverage and spatial distribution analysis. HD and HMD showed brain asymmetry tendency, but in opposite directions. The size of affected hemisphere and the hamartomatous appearance of the WM were the more relevant signs to differentiate both conditions.
BACKGROUND AND PURPOSE: Hemispheric dysplasia (HD) and hemimegalencephaly (HME) are both brain malformations with early clinical manifestation including developmental delay and intractable epilepsy. Sometimes the differentiation of these conditions is not simple. HME is an anomaly of cortical development caused by a combination of neural proliferation and cell migration dysfunction, showing lobar or hemispheric enlargement. On the other hand, HD shows no brain hypertrophy, and even brain atrophy, eventually. PATIENTS AND METHODS: To compare both conditions, we reviewed clinical, MRI, and histopathology of 23 patients with developmental delay and refractory epilepsy treated with hemispheric surgery. RESULTS: Histologically, both groups presented polymicrogyria, focal cortical dysplasia, gray matter (GM) heterotopia, pachygyria, and agyria. The white matter (WM) showed different degrees of gliosis and myelin impairment. Even though with no specificity in histopathology, the degree of lesion was more impressive on HME. The combination of WM dysmyelination and hypertrophy leads to the so called hamartomatous appearing. Although not all HME showed brain enlargement and some HD might show no size changes or atrophy, the size of affected hemisphere and the hamartomatous appearance of the WM were the more relevant signs to differentiate both conditions. CONCLUSION: Brain MRI was the best diagnostic tolls because it allowed together high contrast resolution, whole brain coverage and spatial distribution analysis. HD and HMD showed brain asymmetry tendency, but in opposite directions. The size of affected hemisphere and the hamartomatous appearance of the WM were the more relevant signs to differentiate both conditions.
Authors: David D Broumandi; Ulrike M Hayward; James M Benzian; Ignacio Gonzalez; Marvin D Nelson Journal: Radiographics Date: 2004 May-Jun Impact factor: 5.333
Authors: Vera C Terra-Bustamante; Regina M F Fernandes; Luciana M Inuzuka; Tonicarlo R Velasco; Veriano Alexandre; Lauro Wichert-Ana; Sandra Funayama; Eliana Garzon; Antonio C Santos; David Araujo; Roger Walz; João A Assirati; Helio R Machado; Américo C Sakamoto Journal: Childs Nerv Syst Date: 2005-05-19 Impact factor: 1.475
Authors: Ingmar Blümcke; Maria Thom; Eleonora Aronica; Dawna D Armstrong; Harry V Vinters; Andre Palmini; Thomas S Jacques; Giuliano Avanzini; A James Barkovich; Giorgio Battaglia; Albert Becker; Carlos Cepeda; Fernando Cendes; Nadia Colombo; Peter Crino; J Helen Cross; Olivier Delalande; François Dubeau; John Duncan; Renzo Guerrini; Philippe Kahane; Gary Mathern; Imad Najm; Ciğdem Ozkara; Charles Raybaud; Alfonso Represa; Steven N Roper; Noriko Salamon; Andreas Schulze-Bonhage; Laura Tassi; Annamaria Vezzani; Roberto Spreafico Journal: Epilepsia Date: 2010-11-10 Impact factor: 5.864