Periventricular nodular grey matter heterotopia
There is a focal area of abnormal grey matter localisation at the edge of the left frontal horn of lateral ventricle with its slight extension. It looks like a nodule with a signal characteristic relevant to normal grey matter on all sequences. The rest of the brain seems unremarkable.
Gray matter heterotopia is a relatively common form of neuronal migration disorder in which collections of cortical neurons are found in an abnormal location. It results from an in utero arrest of radial migration of neurons from the germinal matrix in the wall of the lateral ventricle to the developing cerebral cortex between 6 and 16 weeks of gestation. It is usually discovered during the evaluation of children or young adults with epilepsy, children with neurodevelopmental abnormalities, or as an incidental finding like in this case. The pathogenic mechanisms of gray matter heterotopia are not fully understood, but they lead to distinct clinicoradiological syndromes.