We describe a patient with seronegative autoimmune limbic encephalitis (SNALE) masquerading as glioma. Brain magnetic resonance imaging (MRI) abnormalities, distinctive pathological findings, and spontaneous remission are highlighted.
There are 15 previously reported SNALE cases, 1 with pathology.
A 66-year-old man presented with prominent amnestic syndrome, progressive cognitive decline, and refractory complex partial seizures.
Initial brain MRI suggested herpes limbic encephalitis. A 3-week course of intravenous acyclovir was ineffective. Cerebrospinal fluid analysis revealed no pleocytosis. Repeat brain MRI showed a left uncal-hippocampal, contrast-enhancing lesion with mass effect, which was resected. Pathology revealed perivascular and parenchymal mixed lymphocytic inflammatory infiltrates, microglial nodules, neuronophagia, microglial activation, astrocytosis, and lymphocyte emperipolesis within neurons. Thorough searches for infectious pathogens and autoantibodies were negative. Six weeks later, a new enhancing right mesial temporal lesion appeared, with increased seizure activity and further cognitive impairment. Although immune therapy was declined, spontaneous resolution of the new enhancing lesion, with full seizure control and significant cognitive improvement, occurred.
SNALE may masquerade as glioma. Pathologic changes in our case of SNALE are distinctive. Spontaneous resolution of a focal SNALE lesion may potentially occur without immune therapy.
Departments of Neurology, Pathology (Division of Neuropathology), Neurosurgery & Psychiatry, NYU-Comprehensive Epilepsy Center, New York University School of Medicine, New York, NY
Disclosures: No funding was received for this work from the National Institutes of Health (NIH), the Wellcome Trust, Howard Hughes Medical Institute (HHMI), or any other source.
Reprints: Souhel Najjar, MD, NYU School of Medicine—NYU Comprehensive Epilepsy Center, 223 E. 34th St, New York, NY 10016 (e-mail: firstname.lastname@example.org).
Received February 7, 2011
Accepted May 14, 2011