Frans Leijten

Brain surgery is the only curative treatment for people with focal epilepsy, but it is unclear whether this induces active disease in multiple sclerosis (MS). This creates a barrier to evaluate MS patients for epilepsy surgery. We present two cases of successful epilepsy surgery in patients with pharmacoresistant epilepsy and stable MS and give an overview of the existing literature. (1) a 28‐year‐old woman with seizures arising from a right basal temporo‐occipital ganglioglioma was seizure‐free after surgery, without MS relapse but with one new MS lesion postsurgically. (2) a 46‐year‐old woman with seizures arising from a natalizumab‐associated progressive multifocal leukoencephalopathy (PML) lesion in the right frontal lobe was seizure‐free after surgery preceded by extraoperative subdural electrocorticography, with new subclinical MS lesions. We are the first to report brain surgery in a PML survivor. Both patients stabilized radiologically after initiating second‐line therapies. Successful epilepsy surgery can substantially increase the quality of life in patients with pharmacoresistant epilepsy and MS. With increasing survival rates of brain tumors and PML, the risk–benefit ratio of epilepsy surgery compared to a potential MS relapse after surgery becomes critically important. Shared decision‐making is valuable for balancing the risks related to both diseases.