Imaging and radiological-pathological correlation in histologically provencases of focal cortical dysplasia and other glial and neuronoglial malformative lesions in adults

Focal cortical dysplasia (FCD) is a pathological entity first described in 1971. Other more subtle cortical malformations found in patients with epile psy include microdysgenesis (MD), and glioneuronal hamartias. Although thes e glial and neuronoglial malformations have distinct histological features, there is terminological confusion in the radiological literature. Few case s have been reported in adults with both imaging and histology. We address these issues, giving a radiological-pathological correlation of histologica lly proven cortical malformations in adults. We describe clinical, radiolog ical and histological features of 12 cases (five FCD, five MD with glioneur onal hamartias, and two hamartomas), unassociated with other conditions, an d discuss them in the light of the literature. FCD is usually seen on MRI a s cortical thickening, with or without signal change, which may extend into the adjacent white matter. On histology, abnormal neurons and/or glial cel ls, blurring of the grey-white matter interface, myelin pallor, demyelinati on, and gliosis may be found. Glioneuronal hamartias and hamartomas usually appear as complex masses on MRI. FCD and hamartias may be associated, and a combination of imaging findings may be seen on MRI. Atrophy of the ipsila teral hippocampus may be present on MRI in patients with hamartias, and min or cell loss on histology, but not definitive hippocampal sclerosis. Althou gh the imaging findings of cortical malformations are protean, some charact eristic MRI features, with histological correlates, may be found. The relev ance of most of these observations remains unclear.