Focal cortical dysplasia type IIIc associates with multiple cerebral cavernomas.

The distinction of isolated malformations and combined lesions constitutes a major novelty in the 2011 consensus classification of the International League against Epilepsy (ILAE) for focal cortical dysplasias (FCD). Cortical lamination abnormalities together with vascular lesions are subsumed as FCD IIIc. Little is known regarding frequency and etiology of this entity. Here, we systematically evaluated biopsy specimens from 72 drug-refractory epilepsy patients with cerebral cavernous malformations (CCM) regarding presence of associated FCD. Due to a non-perpendicular orientation of the cortical structures or absence of sufficient cortical tissue adjacent to the vascular lesion 25 samples were not classifiable. In the remaining 47 cases FCD IIIc was rare (4.3%), but significantly increased in patients with multiple CCM (28.6%; p<0.05 vs. single CCM). Association of FCD IIIc with multiple CCM may argue against FCD IIIc as an acquired lesion.