A 54-year-old woman, with relapsing Mantle B-cell Lymphoma, was admitted for recurrent unresponsive episodes. During video-EEG recording, patient became transitory unresponsive for 12 minutes with starring and brachiofacial automatisms (video), with correlated diffuse EEG delta activity that resolved spontaneously, without epileptic discharge, cardiac arrhythmia, or hypotension (figure). No intracranial lesion existed on neuroimaging. Lumbar puncture revealed increased CSF pressure and infiltrating lymphomatous cells, confirming a diagnosis of leptomeningeal metastases. Transient neurological events can be linked to increased intracranial pressure generating a decrease of cerebral perfusion and EEG "plateau-waves" 1-5. EEG allow to distinguish this entity from differential diagnoses.