Gliomatosis cerebri mimicking Rasmussen encephalitis

Gliomatosis cerebri (GC) is a distinct malignant neuroepithelial neoplasm that is rarely found in children. The authors present the case of an 11-year-old girl in whom the initial presentation suggested possible early Rasmussen encephalitis (RE), but in whom a diagnosis of GC was made instead after examination of a brain biopsy specimen. Despite advances in magnetic resonance (MR) imaging and MR spectroscopy, this case shows the limitations of clinical and neuroimaging diagnosis and the essential role of biopsy procedures when early RE is suspected.