Frontomesial and orbitofrontal epilepsy

Frontal lobe epilepsy (FLE) constitutes a heterogeneous entity with distinct epilepsy subtypes based on the anatomofunctional organization of the frontal cortical areas. Initially, surgery for extratemporal lobe epilepsy showed less favorable outcomes compared to temporal lobe epilepsy. However, since the appreciation of these electroclinical subtypes with superior localization strategies based on technological advances and invasive intracranial studies, improved clinical outcomes have been reported. In this review we discuss the contemporary clinical concepts of two rare subtypes of FLE, orbitofrontal epilepsy (OFE) and frontomesial cingulate epilepsy (FME). We describe the structural and functional anatomy and connectivity with direct implications on electroclinical characterization. Furthermore, we discuss noninvasive and invasive localization concepts and surgical considerations and outcomes. We present a conceptual framework for OFE and FME, which, due to their hidden anatomical location and extensive connectivity fingerprint, share specific diagnostic and therapeutic challenges. This framework makes it possible to generate anatomo-electroclinical correlation hypotheses from a network perspective in order to identify and target the presumed epileptogenic zone. The combination of a particularly challenging patient group with often favorable outcomes after surgery emphasizes the importance of early referral to specialized epilepsy surgery centers.