Heterotopia-MRI

23 year old lady with seizures on MRI presents grossly nodular subependymmal margins of the lateral ventricles particularly in the trigones and occipital horns with isointense signals to grey matter with hypoplasia of corpus callosum suggesting grey matter heterotopia of subependymal variety.

Teaching points by Dr MGK Murthy :

Ø  Also known as periventricular heterotopia. X-linked recessive gene possibly responsible. Affected males usually do not survive on account of associated anomalies. Affected females suggest cognitive dysfunction as well with seizures.

Ø  The nodules represent clusters of neurons and supporting glial cells in the course of abnormal neuronal migration.

Ø  Right ventricle is more affected then the left (neurons migrate right later than left). The types include unilateral, bilateral or focal and diffuse varietis.

Ø  Antenatal MR could identify easily after 26 weeks (prior to this germinal matrix could simulate the condition). Differentials include hamartomata of tubers or Giant cell astrocytoma or normal variation.