Abstracts

Rationale: Patients with systemic cancer may have new onset status epilepticus (SE) as the main clinical feature of a paraneoplastic encephalitis. Five such patients who underwent MRI during the SE or immediately after recovering are described. Methods: We retrospectively reviewed the MRI of five patients who suffered a SE as the onset of a paraneoplastic encephalitis during the last 6 years in our hospital. All of them fulfilled criteria for paraneoplastic syndrome. Two out of three patients with small-cell lung carcinoma had Anti-Hu antibodies. Two more cases had intestinal and lung adenocarcinoma. SE was convulsive for two patients and none-convulsive for three. Results: All patients showed hyperintense lesions in T2-weighted images (T2WI) involving the limbic structures, specifically the hippocampus. Three of them showed further scattered extralimbic areas of encephalitis. The T2WI hyperintensities were related to the electroclinical onset of the seizures. Perfusion obtained by arterial spin labeling (ASL) in one patient showed hyperperfusion overlapping the inflammatory lesions. When performed, SPECT and PET observed increased metabolism limited to the areas of encephalitis. Mild to moderate contrast enhancement was seen in some patients. After recovering we observed atrophy in the hippocampus involved. Two patients had recurrences of the paraneoplastic encephalitis as SE, showing new T2WI lesions with a different topography. Conclusions: The presence of limbic and extralimbic encephalitis can be suggestive of paraneoplastc syndrome in new onset SE. Lesions are constantly seen as hyperintense in T2WI, can show mild contrast enhancement and increased perfusion or metabolism as seen by ASL or PET/SPECT.