The Gliomatosis Cerebri (GC) is an infiltrating and rare primitive tumour of the brain. It is characterized by diffuse neoplastic proliferation of glial cells involving of at least two lobes of the brain, without a distinct tumor mass and with the preservation of the anatomical and neuronal architecture. According to the WHO classification, GC is categorized as a high-grade neuroepithelial tumor of uncertain origin (GradelV). Now the diagnosis is facilitated via stereotactic biopsies of the representative lesion identified in magnetic resonance. Our objective is to present 4 new cases, and recall the clinical and radiological features and the prognosis.