[P08.051] Reversible Tumor-Like Lesions Induced by Presenting Status Epilepticus

Nuno Canas, Ricardo Pestana, Sofia Calado, José Vale, Constança Ribeiro, Lisbon, Portugal

OBJECTIVE: Describe the MRI follow-up studies in patients with tumor-like lesions induced by presenting status epilepticus (SE). BACKGROUND: Reversible tumor-like lesions induced by SE have been rarely described. In patients without history of epilepsy presenting with SE they cause a diagnostic challenge (cause/consequence of SE?). The recognition of their neuroimaging features may avoid invasive diagnostic studies and allow new insights about the SE-induced pathophysiologic changes. DESIGN/METHODS: We identified four non-epileptic patients with presenting SE associated with tumor-like MRI signal abnormalities that completely/partially reversed in a second MRI. Follow-up MRI studies were performed to investigate their long-term consequences. RESULTS: Three patients presented with convulsive SE (generalized tonic-clonic seizures in two, partial-motor in one), one with partial-complex SE. Patients with partial seizures had clinical-lesional correlation (hippocampus/ precentral lesions); temporal/ parieto-occipital lesions were disclosed in the patients with generalized seizures. Initial MRI (within 24h pos-SE) showed cortico-subcortical (2/4)/ subcortical (2/4) signal abnormalities, increased in T2-weighted (4/4), FLAIR (4/4) and diffusion-weighted (3/3) images, and decreased in the ADC (2/2) and T1-weighted (4/4) images (1/2 with contrast enhancement); MR spectroscopy (MRS) disclosed decreased N-acetylaspartate and elevated choline (2/2) and lactate (1/2); all had sulci effacement. Follow-up MRIs showed complete reversal of the tumor-like signal abnormalities. Three patients had cerebral atrophy in the regions previously affected, with MRS showing a mild recovery of choline/ NAA levels and lactate normalization. Two patients disclosed marked generalized cerebral atrophy. None patient had seizure recurrence. CONCLUSIONS/RELEVANCE: Tumor-like signal abnormalities induced by SE resemble those of isquemic stroke, but do not respect vascular territories; the absence of significant mass effect/ contrast enhancement may help in the differential diagnosis with neoplastic lesions. The MRI features suggest that reversible brain edema and metabolic dysfunction are involved in their pathophysiology; subsequent brain atrophy and NAA decrease discloses permanent neuronal loss.
Category - Epilepsy
SubCategory - Imaging

Thursday, May 3, 2007 4:00 PM

Poster Sessions: Epilepsy V (4:00 PM-7:00 PM)

The embargo for all abstracts to be presented at the 59th Annual Meeting is in effect until the date and time of the presentation unless otherwise noted on the abstract and/or press release. If there are questions, please contact the AAN media and public relations team.