RESUMO
A 75-year-old woman developed a frontal lobe disorder a few days after the diagnostic of an Acute Myeloid Leukemia secondary to a myelodysplastic syndrome. The patterns on the cerebral Magnetic Resonance Imaging and positron emission tomography and the find of antiglutamic acid decarboxylase antibody on cerebral spinal fluid were in favor of a paraneoplastic limbic encephalitis. In cerebral spinal fluid, there were no micro-organisms nor leukemic cells. We found no sign of cancer on full body computerized tomography-scan, on full-body PET and on rectosigmoidoscopy. The patient was treated by corticosteroid and intravenous immunoglobulins with success, but she died before receiving chemotherapy. It's known that anti- glutamic acid decarboxylase antibody is involved in paraneoplastic syndromes. Paraneoplastic limbic encephalitis is frequently associated with carcinoma or Hodgkin's lymphoma, but it was only reported associated with Acute Myeloid Leukemia in one case report. Even if Acute Myeloid Leukemia is not frequently associated with paraneoplastic limbic encephalitis, the clinicians must consider paraneoplastic limbic encephalitis as an etiology of unexplained neurological disorders.