Mild malformation of cortical development with oligodendroglial hyperplasia and epilepsy (MOGHE): a widespread disease with an apparently focal epilepsy

Abstract

Mild malformation of cortical development with oligodendroglial hyperplasia and epilepsy (MOGHE) is a recently recognized, highly epileptogenic, distinct histopathological entity in drug-resistant epilepsy that primarily involves the frontal lobes. Surgical outcomes in MOGHE are variable. Although the diagnosis is based on histopathology, high-resolution MRI helps to differentiate MOGHE preoperatively from other forms of cortical malformations (i.e., mMCD II and FCD IIa). We discuss the clinical, electrographic, radiological and histopathological characteristics of MOGHE in two patients who underwent evaluation for drug-resistant epilepsy followed by electrocorticography-based resection. Both patients presented with childhood-onset refractory frontal lobe epilepsy with a high seizure burden. Interictal epileptiform discharges were widespread. PET abnormalities were disproportionate to the MRI findings. Cognitive impairment, persistent epileptiform discharges on post-resection electrocorticography and sub-optimal surgical outcomes suggest that MOGHE is a widespread pathology in focal epilepsy.

The ILAE consensus classification of focal cortical dysplasia: An update proposed by an ad hoc task force of the ILAE diagnostic methods commission

“…Mild malformations of cortical development with oligodendroglial hyperplasia in epilepsy (or MOGHE) is defined by an increase in heterotopic neurons in the white matter and oligodendroglial cell densities above 2200 Olig2‐immunoreactive cells per mm 2 20,22–24,99–101 (Figure 5D). Reported cases involve young children with frontal lobe epilepsy, or temporal plus epilepsy, with a median seizure onset at age 2 years (range 0.3–13 years) 20 .…”

Frontal lobe epilepsy and mild malformation with oligodendroglial hyperplasia: Further observations on electroclinical and imaging phenotypes, and surgical perspectives

“…Mild Malformation with Oligodendroglial Hyperplasia (MOGHE) has been recently described, as a distinct clinicopathologic entity in adult and pediatric epilepsy patients, most of them with Frontal Lobe Epilepsy [1][2][3][4][5][6][7][8] as well as with "Temporal plus" 9 occipitotemporal, 10,11 and Epileptic Encephalopathy 7 electroclinical phenotypes. Although MRI features in some cases suggest FCD IIa type, 3 on histopathologic grounds MOGHE is an entity distinct from FCD, its cardinal features consist of normal cortical architecture, increased oligodendrocyte numbers and proliferative activity in the deep cortical layers and superficial white matter, heterotopic neurons in the white matter, as well as cortical-white matter blurring and hypomyelinated white matter areas.…”

The proportion of seizure onset zone contacts resected is not associated with outcome following SEEG-guided resective epilepsy surgery in children

“…Alternatively, it could be that there are alternative pathological entities that are newly being identified such as mild malformation of cortical development with oligodendroglial hyperplasia and epilepsy (MOGHE), associated with poorer outcomes. 16 The results also highlight the difficulty of ensuring that all intended contacts are resected following SEEG. Whilst some of the variability may be down to registration error, resecting intended contacts may be limited by functional boundaries or geographically separated contacts which are not all amenable to being resected.…”

“…Alternatively, it could be that there are alternative pathological entities that are newly being identified such as mild malformation of cortical development with oligodendroglial hyperplasia and epilepsy (MOGHE), associated with poorer outcomes. 16…”