While surgery is proned in low-grade glioma (LGG), the invasion of functional areas frequently prevents a complete resection. We report the first case of a patient operated on for a left frontal LGG, diagnosed because of seizures, with partial resection due to an invasion of the controlateral hemisphere. Chemotherapy enabled a regression of this controlateral extension. Postchemotherapy surgery performed with intraoperative functional mapping then allowed a complete resection, without sequelae. The patient has a normal socio-professional life, with no seizure. No other treatment was given. There was no recurrence, with a follow-up of 2 years since the second surgery (3.5 years since the first symptom). We propose a new therapeutic strategy in unresectable LGG, with preoperative chemotherapy, to make a radical surgery possible in a second step, while preserving the quality of life.